feat: locks/replace/compare/permalinks; perf: virtualization, LQIP, caching, diagnostics; add tests, docs, and issue/PR templates (flags OFF)

.gitignore

@@ -4,6 +4,7 @@
 *.txt
 .mypy_cache/
 .venv/
+.pytest_cache/
 test.py
 !requirements.txt
 __pycache__/

CHANGELOG.md

@@ -13,7 +13,18 @@ This format follows Keep a Changelog principles and aims for Semantic Versioning
 ## [Unreleased]
 
 ### Added
+- Web UI performance: optional virtualized grids/lists in Step 5 and Owned (enable with `WEB_VIRTUALIZE=1`).
+- Virtualization diagnostics overlay (when `SHOW_DIAGNOSTICS=1`); press `v` to toggle per‑grid overlays and a global summary bubble with visible range, totals, render time, and counters.
+- Image polish: lazy‑loading with responsive `srcset/sizes` and LQIP blur/fade‑in for Step 5 and Owned thumbnails and the commander preview image.
+- Short‑TTL fragment caching for template partials (e.g., finished deck summaries and config run summaries) to reduce re‑render cost.
 - Web UI: FastAPI + Jinja front-end for the builder; staged build view with per-stage reasons
+- New Deck modal consolidating steps 1–3 with optional Name for exports, Enter-to-select commander, and disabled browser autofill
+- Locks, Replace flow, Compare builds, and shareable permalinks for finished decks
+- Compare page: Copy summary action to copy diffs (Only in A/B and Changed counts) to clipboard
+ - Finished Decks multi-select → Compare with fallback to "Latest two"; options carry modified-time for ordering
+ - Permalinks include locks; global "Open Permalink…" entry exposed in header and Finished Decks
+ - Replace flow supports session-local Undo and lock-aware validation
+- New Deck modal: inline summary of selected themes with order (1, 2, 3)
 - Theme combine mode (AND/OR) with tooltips and selection-order display in the Web UI
 - AND-mode creatures pre-pass: select "all selected themes" creatures first, then fill by weighted overlap; staged reasons show matched themes
 - Scryfall attribution footer in the Web UI
@@ -39,7 +50,11 @@ This format follows Keep a Changelog principles and aims for Semantic Versioning
  - `/status/logs?tail=N` endpoint (read-only) to fetch a recent log tail for quick diagnostics
  - Tooltip Copy action on chart tooltips (Pips/Sources) for quick sharing of per-color card lists
 
+Roadmap and usage for Web UI features are tracked in `logs/web-ui-upgrade-outline.md`.
+
 ### Changed
+- Accessibility: respect OS “reduced motion” by disabling blur/fade transitions and smooth scrolling.
+- Static asset caching and compression tuned for the web service (cache headers + gzip) to improve load performance.
 - Rename folder from `card_library` to `owned_cards` (env override: `OWNED_CARDS_DIR`; back-compat respected)
 - Docker assets and docs updated:
   - New volume mounts: `./owned_cards:/app/owned_cards` and `./config:/app/config`
@@ -51,6 +66,12 @@ This format follows Keep a Changelog principles and aims for Semantic Versioning
  - Builder Review (Step 4): "Use only owned cards" toggle moved here; Step 5 is status-only with "Edit in Review" for changes
  - Minor UI/CSS polish and consolidation across builder/owned pages
  - Deck summary reporting now includes colorless 'C' in totals and cards; UI adds a Show C toggle for Sources
+ - New Deck modal submits directly to build, removing the intermediate review step
+ - Finished Decks banner and lists now prefer the custom Name provided in the modal
+ - Step 5 Replace toggle now includes a tooltip clarifying that reruns will replace picks in that stage when enabled
+ - Locks are enforced on rerun; the Locked section live-updates on unlock (row removal and chip refresh)
+ - Compare page shows ▲/▼ indicators on Changed counts and preserves the "Changed only" toggle across interactions
+ - Bracket selector shows numbered labels (e.g., "Bracket 3: Upgraded") and defaults to bracket 3 on new deck creation
  - List view highlight polished to wrap only the card name (no overrun of the row)
  - Total sources calculation updated to include 'C' properly
  - 404s from Starlette now render the HTML 404 page when requested from a browser (Accept: text/html)
@@ -66,7 +87,9 @@ This format follows Keep a Changelog principles and aims for Semantic Versioning
  - Basics handling: ensured basic lands and Wastes are recognized as sources; added fallback oracle text for basics in CSV export
  - Fetch lands are no longer miscounted as mana sources
  - Web 404s previously returned JSON to browsers in some cases; now correctly render HTML via a Starlette HTTPException handler
+ - Windows PowerShell curl parsing issue documented with guidance in README
  - Deck summary alignment issues in some sections (e.g., Enchantments) fixed by splitting the count and the × into separate columns and pinning the owned flag to a fixed width; prevents drift across responsive breakpoints
+ - Banned list filtering applied consistently to all color/guild CSV generation paths with exact, case-insensitive matching on name/faceName (e.g., Hullbreacher, Dockside Extortionist, and Lutri are excluded)
 
 ---
 

DOCKER.md

@@ -34,6 +34,36 @@ Then open http://localhost:8080
 
 Volumes are the same as the CLI service, so deck exports/logs/configs persist in your working folder.
 The app serves a favicon at `/favicon.ico` and exposes a health endpoint at `/healthz`.
+Compare view offers a Copy summary button to copy a plain-text diff of two runs.
+
+Web UI feature highlights:
+- Locks: Click a card or the lock control in Step 5; locks persist across reruns.
+- Replace: Enable Replace in Step 5, click a card to open Alternatives (filters include Owned-only), then choose a swap.
+- Permalinks: Copy a permalink from Step 5 or a Finished deck; paste via “Open Permalink…” to restore.
+- Compare: Use the Compare page from Finished Decks; quick actions include Latest two and Swap A/B.
+
+Virtualized lists and lazy images (opt‑in)
+- Set `WEB_VIRTUALIZE=1` to enable virtualization in Step 5 grids/lists and the Owned library for smoother scrolling on large sets.
+- Example (Compose):
+    ```yaml
+    services:
+        web:
+            environment:
+                - WEB_VIRTUALIZE=1
+    ```
+- Example (Docker Hub):
+    ```powershell
+    docker run --rm -p 8080:8080 `
+        -e WEB_VIRTUALIZE=1 `
+        -v "${PWD}/deck_files:/app/deck_files" `
+        -v "${PWD}/logs:/app/logs" `
+        -v "${PWD}/csv_files:/app/csv_files" `
+        -v "${PWD}/owned_cards:/app/owned_cards" `
+        -v "${PWD}/config:/app/config" `
+    -e SHOW_DIAGNOSTICS=1 ` # optional: enables diagnostics tools and overlay
+    mwisnowski/mtg-python-deckbuilder:latest `
+        bash -lc "cd /app && uvicorn code.web.app:app --host 0.0.0.0 --port 8080"
+    ```
 
 ### Diagnostics and logs (optional)
 Enable internal diagnostics and a read-only logs viewer with environment flags.
@@ -44,6 +74,7 @@ Enable internal diagnostics and a read-only logs viewer with environment flags.
 When enabled:
 - `/logs` supports an auto-refresh toggle with interval, a level filter (All/Error/Warning/Info/Debug), and a Copy button to copy the visible tail.
 - `/status/sys` returns a simple system summary (version, uptime, UTC server time, and feature flags) and is shown on the Diagnostics page when `SHOW_DIAGNOSTICS=1`.
+ - Virtualization overlay: press `v` on pages with virtualized grids to toggle per-grid overlays and a global summary bubble.
 
 Compose example (web service):
 ```yaml
@@ -125,6 +156,8 @@ GET http://localhost:8080/healthz  ->  { "status": "ok", "version": "dev", "upti
 ### Web UI tuning env vars
 - WEB_TAG_PARALLEL=1|0 (parallel tagging on/off)
 - WEB_TAG_WORKERS=<N> (process count; set based on CPU/memory)
+- WEB_VIRTUALIZE=1 (enable virtualization)
+- SHOW_DIAGNOSTICS=1 (enables diagnostics pages and overlay hotkey `v`)
 
 ## Manual build/run
 ```powershell

Dockerfile

@@ -48,3 +48,7 @@ WORKDIR /app/code
 
 # Run the application
 CMD ["python", "main.py"]
+
+# Note: For the Web UI, start uvicorn in your orchestrator (compose/run) like:
+#   uvicorn code.web.app:app --host 0.0.0.0 --port 8080
+# Phase 9: enable web list virtualization with env WEB_VIRTUALIZE=1

RELEASE_NOTES_TEMPLATE.md

@@ -8,6 +8,10 @@
 - Exports: CSV/TXT always; JSON run-config exported for interactive runs and optionally in headless (`HEADLESS_EXPORT_JSON=1`).
 - Data freshness: Auto-refreshes `cards.csv` if missing or older than 7 days and re-tags when needed using `.tagging_complete.json`.
 - Web setup speed: initial tagging runs in parallel by default for the Web UI. Configure with `WEB_TAG_PARALLEL=1|0` and `WEB_TAG_WORKERS=<N>` (compose default: 4). Falls back to sequential if parallel init fails.
+ - Phase 8 UI upgrade: Unified “New Deck” modal (steps 1–3), Locks, Replace flow, Compare builds, and shareable Permalinks. Optional Name field becomes the export filename stem and display name.
+  - Compare page now includes a Copy summary button to quickly share diffs.
+  - New Deck modal: shows selected themes and their order (1, 2, 3) inline while picking.
+ - Commander search UX: press Enter to select the first suggestion; arrow key navigation removed per feedback; browser autofill disabled.
  - Visual summaries: Mana Curve, Color Pips and Sources charts with hover-to-highlight and copyable tooltips. Sources now include non-land producers and colorless 'C' (toggle display in UI). Basic lands reliably counted; fetch lands no longer miscounted as sources.
  - Favicon support: app branding icon served at `/favicon.ico` (ICO/PNG fallback).
  - Prefer-owned option in the Web UI Review step prioritizes owned cards while allowing unowned fallback; applied across creatures and spells with stable reordering and gentle weight boosts.
@@ -16,6 +20,10 @@
  - Owned page UX: hover preview now triggers from the thumbnail, not the name; selection outline is restricted to the thumbnail and uses white for clarity; hover popout shows Themes as a larger bullet list with a bright label.
  - Image robustness: all Scryfall images include `data-card-name` and participate in centralized retry (version fallback + one cache-bust) for thumbnails and previews.
  - Deck Summary: aligned text-mode list (fixed columns for count/×/name/owned), highlight that doesn’t shift layout, and tooltips for truncated names. The list begins directly under each type header for better scanability.
+ - Finished Decks: banner and lists prefer the run’s custom Name when provided; runs include a sidecar `.summary.json` with `meta.name` for display.
+  - Replace toggle includes a tooltip explaining that reruns will replace that stage’s picks when enabled.
+  - Bracket selector labels now include numbers (e.g., "Bracket 3: Upgraded"). Default bracket is 3 when creating a new deck.
+ - Exports: CSV/TXT/JSON now share the same filename stem derived from the optional Name in the modal.
 
 ### Diagnostics and error handling
 - Health endpoint `/healthz` returns `{ status, version, uptime_seconds }`.
@@ -91,6 +99,7 @@ docker compose up --no-deps web
  - Finished Decks page uses a dropdown theme filter with shareable state.
  - Global image retry binding for all card images (thumbnails and previews), with no JS hover cache to minimize memory and complexity.
  - Deck Summary fixes: separated count and × into distinct columns, fixed-width owned indicator, and responsive stability at fullscreen widths.
+ - Data integrity: per-color/guild CSVs now consistently respect the Commander banned list using exact, case-insensitive name/faceName matching.
 
 ### Tagging updates
 - Explore/Map: treat "+1/+1 counter" as a literal; Explore adds Card Selection and may add +1/+1 Counters; Map adds Card Selection and Tokens Matter.

WINDOWS_DOCKER_GUIDE.md

@@ -46,6 +46,7 @@ Run the browser UI by mapping a port and starting uvicorn:
 ```powershell
 docker run --rm `
   -p 8080:8080 `
+  -e WEB_VIRTUALIZE=1 ` # optional virtualization
   -v "${PWD}/deck_files:/app/deck_files" `
   -v "${PWD}/logs:/app/logs" `
   -v "${PWD}/csv_files:/app/csv_files" `

code/deck_builder/phases/phase6_reporting.py

@@ -343,6 +343,15 @@ class ReportingMixin:
                     return candidate
                 i += 1
         if filename is None:
+            # Build a filename stem from either custom export base or commander/themes
+            try:
+                custom_base = getattr(self, 'custom_export_base', None)
+            except Exception:
+                custom_base = None
+            date_part = _dt.date.today().strftime('%Y%m%d')
+            if isinstance(custom_base, str) and custom_base.strip():
+                stem = f"{_slug(custom_base.strip())}_{date_part}"
+            else:
                 cmdr = getattr(self, 'commander_name', '') or getattr(self, 'commander', '') or ''
                 cmdr_slug = _slug(cmdr) if isinstance(cmdr, str) and cmdr else 'deck'
                 # Collect themes in order
@@ -357,8 +366,8 @@ class ReportingMixin:
                 if not theme_parts:
                     theme_parts = ['notheme']
                 theme_slug = '_'.join(theme_parts)
-            date_part = _dt.date.today().strftime('%Y%m%d')
-            filename = f"{cmdr_slug}_{theme_slug}_{date_part}.csv"
+                stem = f"{cmdr_slug}_{theme_slug}_{date_part}"
+            filename = f"{stem}.csv"
         fname = _unique_path(os.path.join(directory, filename))
 
         full_df = getattr(self, '_full_cards_df', None)
@@ -534,6 +543,15 @@ class ReportingMixin:
                     return candidate
                 i += 1
         if filename is None:
+            # Prefer custom export base if provided; else fall back to commander/themes
+            try:
+                custom_base = getattr(self, 'custom_export_base', None)
+            except Exception:
+                custom_base = None
+            date_part = _dt.date.today().strftime('%Y%m%d')
+            if isinstance(custom_base, str) and custom_base.strip():
+                stem = f"{_slug(custom_base.strip())}_{date_part}"
+            else:
                 cmdr = getattr(self, 'commander_name', '') or getattr(self, 'commander', '') or ''
                 cmdr_slug = _slug(cmdr) if isinstance(cmdr, str) and cmdr else 'deck'
                 themes: List[str] = []
@@ -547,8 +565,8 @@ class ReportingMixin:
                 if not theme_parts:
                     theme_parts = ['notheme']
                 theme_slug = '_'.join(theme_parts)
-            date_part = _dt.date.today().strftime('%Y%m%d')
-            filename = f"{cmdr_slug}_{theme_slug}_{date_part}.txt"
+                stem = f"{cmdr_slug}_{theme_slug}_{date_part}"
+            filename = f"{stem}.txt"
         if not filename.lower().endswith('.txt'):
             filename = filename + '.txt'
         path = _unique_path(os.path.join(directory, filename))
@@ -643,6 +661,15 @@ class ReportingMixin:
                 i += 1
 
         if filename is None:
+            # Prefer a custom export base when present; else commander/themes
+            try:
+                custom_base = getattr(self, 'custom_export_base', None)
+            except Exception:
+                custom_base = None
+            date_part = _dt.date.today().strftime('%Y%m%d')
+            if isinstance(custom_base, str) and custom_base.strip():
+                stem = f"{_slug(custom_base.strip())}_{date_part}"
+            else:
                 cmdr = getattr(self, 'commander_name', '') or getattr(self, 'commander', '') or ''
                 cmdr_slug = _slug(cmdr) if isinstance(cmdr, str) and cmdr else 'deck'
                 themes: List[str] = []
@@ -656,8 +683,8 @@ class ReportingMixin:
                 if not theme_parts:
                     theme_parts = ['notheme']
                 theme_slug = '_'.join(theme_parts)
-            date_part = _dt.date.today().strftime('%Y%m%d')
-            filename = f"{cmdr_slug}_{theme_slug}_{date_part}.json"
+                stem = f"{cmdr_slug}_{theme_slug}_{date_part}"
+            filename = f"{stem}.json"
 
         path = _unique_path(os.path.join(directory, filename))
 

code/file_setup/setup.py

@@ -208,8 +208,8 @@ def regenerate_csv_by_color(color: str) -> None:
         df = pd.read_csv(f'{CSV_DIRECTORY}/cards.csv', low_memory=False)
 
         logger.info(f'Regenerating {color} cards CSV')
-        # Use shared utilities to base-filter once then slice color
-        base_df = filter_dataframe(df, [])
+        # Use shared utilities to base-filter once then slice color, honoring bans
+        base_df = filter_dataframe(df, BANNED_CARDS)
         base_df[base_df['colorIdentity'] == color_abv].to_csv(
             f'{CSV_DIRECTORY}/{color}_cards.csv', index=False
         )

code/file_setup/setup_utils.py

@@ -36,7 +36,8 @@ from .setup_constants import (
     COLUMN_ORDER,
     TAGGED_COLUMN_ORDER,
     SETUP_COLORS,
-    COLOR_ABRV
+    COLOR_ABRV,
+    BANNED_CARDS,
 )
 from exceptions import (
     MTGJSONDownloadError,
@@ -138,7 +139,8 @@ def save_color_filtered_csvs(df: pd.DataFrame, out_dir: Union[str, Path]) -> Non
 
     # Base-filter once for efficiency, then per-color filter without redoing base filters
     try:
-        base_df = filter_dataframe(df, [])
+        # Apply full standard filtering including banned list once, then slice per color
+        base_df = filter_dataframe(df, BANNED_CARDS)
     except Exception as e:
         # Wrap any unexpected issues as DataFrameProcessingError
         raise DataFrameProcessingError(
@@ -207,10 +209,16 @@ def filter_dataframe(df: pd.DataFrame, banned_cards: List[str]) -> pd.DataFrame:
             filtered_df = filtered_df[~filtered_df['printings'].str.contains(set_code, na=False)]
         logger.debug('Removed illegal sets')
 
-        # Remove banned cards
-        for card in banned_cards:
-            filtered_df = filtered_df[~filtered_df['name'].str.contains(card, na=False)]
-        logger.debug('Removed banned cards')
+        # Remove banned cards (exact, case-insensitive match on name or faceName)
+        if banned_cards:
+            banned_set = {b.casefold() for b in banned_cards}
+            name_lc = filtered_df['name'].astype(str).str.casefold()
+            face_lc = filtered_df['faceName'].astype(str).str.casefold()
+            mask = ~(name_lc.isin(banned_set) | face_lc.isin(banned_set))
+            before = len(filtered_df)
+            filtered_df = filtered_df[mask]
+            after = len(filtered_df)
+            logger.debug(f'Removed banned cards: {before - after} filtered out')
 
         # Remove special card types
         for card_type in CARD_TYPES_TO_EXCLUDE:
@@ -268,7 +276,7 @@ def filter_by_color_identity(df: pd.DataFrame, color_identity: str) -> pd.DataFr
             
         # Apply base filtering
         with tqdm(total=1, desc='Applying base filtering') as pbar:
-            filtered_df = filter_dataframe(df, [])
+            filtered_df = filter_dataframe(df, BANNED_CARDS)
             pbar.update(1)
             
         # Filter by color identity

code/tests/test_alternatives_filters.py

@@ -0,0 +1,68 @@
+import importlib
+from starlette.testclient import TestClient
+
+
+class FakeBuilder:
+    def __init__(self):
+        # Minimal attributes accessed by /build/alternatives
+        self._card_name_tags_index = {
+            'target card': ['ramp', 'mana'],
+            'alt good': ['ramp', 'mana'],
+            'alt owned': ['ramp'],
+            'alt commander': ['ramp'],
+            'alt in deck': ['ramp'],
+            'alt locked': ['ramp'],
+            'unrelated': ['draw'],
+        }
+        # Simulate pandas DataFrame mapping to preserve display casing
+        # Represented as a simple mock object with .empty and .iterrows() for keys above
+        class DF:
+            empty = False
+            def __init__(self, names):
+                self._names = names
+            def __getattr__(self, name):
+                if name == 'empty':
+                    return False
+                raise AttributeError
+            def __iter__(self):
+                return iter(self._names)
+        # We'll emulate minimal API used: df[ df["name"].astype(str).str.lower().isin(pool) ]
+        # To keep it simple, we won't rely on DF in this test; display falls back to lower-case names.
+        self._combined_cards_df = None
+        self.card_library = {}
+        # Simulate deck names containing 'alt in deck'
+        self.current_names = ['alt in deck']
+
+
+def _inject_fake_ctx(client: TestClient, commander: str, locks: list[str]):
+    # Touch session to get sid cookie
+    r = client.get('/build')
+    assert r.status_code == 200
+    sid = r.cookies.get('sid')
+    assert sid
+    # Import session service and mutate directly
+    tasks = importlib.import_module('code.web.services.tasks')
+    sess = tasks.get_session(sid)
+    sess['commander'] = commander
+    sess['locks'] = locks
+    sess['build_ctx'] = {
+        'builder': FakeBuilder(),
+        'locks': {s.lower() for s in locks},
+    }
+    return sid
+
+
+def test_alternatives_filters_out_commander_in_deck_and_locked():
+    app_module = importlib.import_module('code.web.app')
+    client = TestClient(app_module.app)
+    _inject_fake_ctx(client, commander='Alt Commander', locks=['alt locked'])
+    # owned_only off
+    r = client.get('/build/alternatives?name=Target%20Card&owned_only=0')
+    assert r.status_code == 200
+    body = r.text.lower()
+    # Should include alt good and alt owned, but not commander, in deck, or locked
+    assert 'alt good' in body or 'alt%20good' in body
+    assert 'alt owned' in body or 'alt%20owned' in body
+    assert 'alt commander' not in body
+    assert 'alt in deck' not in body
+    assert 'alt locked' not in body

code/tests/test_compare_diffs.py

@@ -0,0 +1,52 @@
+import os
+import tempfile
+from pathlib import Path
+import importlib
+from starlette.testclient import TestClient
+
+
+def _write_csv(p: Path, rows):
+    p.write_text('\n'.join(rows), encoding='utf-8')
+
+
+def test_compare_diffs_with_temp_exports(monkeypatch):
+    with tempfile.TemporaryDirectory() as tmpd:
+        tmp = Path(tmpd)
+        # Create two CSV exports with small differences
+        a = tmp / 'A.csv'
+        b = tmp / 'B.csv'
+        header = 'Name,Count,Type,ManaValue\n'
+        _write_csv(a, [
+            header.rstrip('\n'),
+            'Card One,1,Creature,2',
+            'Card Two,2,Instant,1',
+            'Card Three,1,Sorcery,3',
+        ])
+        _write_csv(b, [
+            header.rstrip('\n'),
+            'Card Two,1,Instant,1',  # decreased in B
+            'Card Four,1,Creature,2',  # only in B
+            'Card Three,1,Sorcery,3',
+        ])
+        # Touch mtime so B is newer
+        os.utime(a, None)
+        os.utime(b, None)
+
+        # Point DECK_EXPORTS at this temp dir
+        monkeypatch.setenv('DECK_EXPORTS', str(tmp))
+        app_module = importlib.import_module('code.web.app')
+        client = TestClient(app_module.app)
+
+        # Compare A vs B
+        r = client.get(f'/decks/compare?A={a.name}&B={b.name}')
+        assert r.status_code == 200
+        body = r.text
+        # Only in A: Card One
+        assert 'Only in A' in body
+        assert 'Card One' in body
+        # Only in B: Card Four
+        assert 'Only in B' in body
+        assert 'Card Four' in body
+        # Changed list includes Card Two with delta -1
+        assert 'Card Two' in body
+        assert 'Decreased' in body or '( -1' in body or '(-1)' in body

code/tests/test_compare_metadata.py

@@ -0,0 +1,12 @@
+import importlib
+from starlette.testclient import TestClient
+
+
+def test_compare_options_include_mtime_attribute():
+    app_module = importlib.import_module('code.web.app')
+    client = TestClient(app_module.app)
+    r = client.get('/decks/compare')
+    assert r.status_code == 200
+    body = r.text
+    # Ensure at least one option contains data-mtime attribute (present even with empty list structure)
+    assert 'data-mtime' in body

code/tests/test_permalinks_and_locks.py

@@ -0,0 +1,44 @@
+import base64
+import json
+from starlette.testclient import TestClient
+
+
+def test_permalink_includes_locks_and_restores_notice(monkeypatch):
+    # Lazy import to ensure fresh app state
+    import importlib
+    app_module = importlib.import_module('code.web.app')
+    client = TestClient(app_module.app)
+
+    # Seed a session with a commander and locks by calling /build and directly touching session via cookie path
+    # Start a session
+    r = client.get('/build')
+    assert r.status_code == 200
+
+    # Now set some session state by invoking endpoints that mutate session
+    # Simulate selecting commander and a lock
+    # Use /build/from to load a permalink-like payload directly
+    payload = {
+        "commander": "Atraxa, Praetors' Voice",
+        "tags": ["proliferate"],
+        "bracket": 3,
+        "ideals": {"ramp": 10, "lands": 36, "basic_lands": 18, "creatures": 28, "removal": 10, "wipes": 3, "card_advantage": 8, "protection": 4},
+        "tag_mode": "AND",
+        "flags": {"owned_only": False, "prefer_owned": False},
+        "locks": ["Swords to Plowshares", "Sol Ring"],
+    }
+    raw = json.dumps(payload, separators=(",", ":")).encode('utf-8')
+    token = base64.urlsafe_b64encode(raw).decode('ascii').rstrip('=')
+    r2 = client.get(f'/build/from?state={token}')
+    assert r2.status_code == 200
+    # Step 4 should contain the locks restored chip
+    body = r2.text
+    assert 'locks restored' in body.lower()
+
+    # Ask the server for a permalink now and ensure locks are present
+    r3 = client.get('/build/permalink')
+    assert r3.status_code == 200
+    data = r3.json()
+    # Prefer decoded state when token not provided
+    state = data.get('state') or {}
+    assert 'locks' in state
+    assert set([s.lower() for s in state.get('locks', [])]) == {"swords to plowshares", "sol ring"}

code/tests/test_replace_and_locks_flow.py

@@ -0,0 +1,68 @@
+import base64
+import json
+import importlib
+from starlette.testclient import TestClient
+
+
+def _decode_permalink_state(client: TestClient) -> dict:
+    r = client.get('/build/permalink')
+    assert r.status_code == 200
+    data = r.json()
+    if data.get('state'):
+        return data['state']
+    # If only permalink token provided, decode it for inspection
+    url = data.get('permalink') or ''
+    assert '/build/from?state=' in url
+    token = url.split('state=', 1)[1]
+    pad = '=' * (-len(token) % 4)
+    raw = base64.urlsafe_b64decode((token + pad).encode('ascii')).decode('utf-8')
+    return json.loads(raw)
+
+
+def test_replace_updates_locks_and_undo_restores(monkeypatch):
+    app_module = importlib.import_module('code.web.app')
+    client = TestClient(app_module.app)
+
+    # Start session
+    r = client.get('/build')
+    assert r.status_code == 200
+
+    # Replace Old -> New (locks: add new, remove old)
+    r2 = client.post('/build/replace', data={'old': 'Old Card', 'new': 'New Card'})
+    assert r2.status_code == 200
+    body = r2.text
+    assert 'Locked <strong>New Card</strong> and unlocked <strong>Old Card</strong>' in body
+
+    state = _decode_permalink_state(client)
+    locks = {s.lower() for s in state.get('locks', [])}
+    assert 'new card' in locks
+    assert 'old card' not in locks
+
+    # Undo should remove new and re-add old
+    r3 = client.post('/build/replace/undo', data={'old': 'Old Card', 'new': 'New Card'})
+    assert r3.status_code == 200
+    state2 = _decode_permalink_state(client)
+    locks2 = {s.lower() for s in state2.get('locks', [])}
+    assert 'old card' in locks2
+    assert 'new card' not in locks2
+
+
+def test_lock_from_list_unlock_emits_oob_updates():
+    app_module = importlib.import_module('code.web.app')
+    client = TestClient(app_module.app)
+
+    # Initialize session
+    r = client.get('/build')
+    assert r.status_code == 200
+
+    # Lock a name
+    r1 = client.post('/build/lock', data={'name': 'Test Card', 'locked': '1'})
+    assert r1.status_code == 200
+
+    # Now unlock from the locked list path (from_list=1)
+    r2 = client.post('/build/lock', data={'name': 'Test Card', 'locked': '0', 'from_list': '1'})
+    assert r2.status_code == 200
+    body = r2.text
+    # Should include out-of-band updates so UI can refresh the locks chip/section
+    assert 'hx-swap-oob' in body
+    assert 'id="locks-chip"' in body or "id='locks-chip'" in body

code/web/app.py

@@ -11,6 +11,8 @@ import time
 import uuid
 import logging
 from starlette.exceptions import HTTPException as StarletteHTTPException
+from starlette.middleware.gzip import GZipMiddleware
+from typing import Any, Tuple
 
 # Resolve template/static dirs relative to this file
 _THIS_DIR = Path(__file__).resolve().parent
@@ -18,10 +20,20 @@ _TEMPLATES_DIR = _THIS_DIR / "templates"
 _STATIC_DIR = _THIS_DIR / "static"
 
 app = FastAPI(title="MTG Deckbuilder Web UI")
+app.add_middleware(GZipMiddleware, minimum_size=500)
 
 # Mount static if present
 if _STATIC_DIR.exists():
-    app.mount("/static", StaticFiles(directory=str(_STATIC_DIR)), name="static")
+    class CacheStatic(StaticFiles):
+        async def get_response(self, path, scope):  # type: ignore[override]
+            resp = await super().get_response(path, scope)
+            try:
+                # Add basic cache headers for static assets
+                resp.headers.setdefault("Cache-Control", "public, max-age=604800, immutable")
+            except Exception:
+                pass
+            return resp
+    app.mount("/static", CacheStatic(directory=str(_STATIC_DIR)), name="static")
 
 # Jinja templates
 templates = Jinja2Templates(directory=str(_TEMPLATES_DIR))
@@ -35,14 +47,42 @@ def _as_bool(val: str | None, default: bool = False) -> bool:
 SHOW_LOGS = _as_bool(os.getenv("SHOW_LOGS"), False)
 SHOW_SETUP = _as_bool(os.getenv("SHOW_SETUP"), True)
 SHOW_DIAGNOSTICS = _as_bool(os.getenv("SHOW_DIAGNOSTICS"), False)
+SHOW_VIRTUALIZE = _as_bool(os.getenv("WEB_VIRTUALIZE"), False)
 
 # Expose as Jinja globals so all templates can reference without passing per-view
 templates.env.globals.update({
     "show_logs": SHOW_LOGS,
     "show_setup": SHOW_SETUP,
     "show_diagnostics": SHOW_DIAGNOSTICS,
+    "virtualize": SHOW_VIRTUALIZE,
 })
 
+# --- Simple fragment cache for template partials (low-risk, TTL-based) ---
+_FRAGMENT_CACHE: dict[Tuple[str, str], tuple[float, str]] = {}
+_FRAGMENT_TTL_SECONDS = 60.0
+
+def render_cached(template_name: str, cache_key: str | None, /, **ctx: Any) -> str:
+    """Render a template fragment with an optional cache key and short TTL.
+
+    Intended for finished/immutable views (e.g., saved deck summaries). On error,
+    falls back to direct rendering without cache interaction.
+    """
+    try:
+        if cache_key:
+            now = time.time()
+            k = (template_name, str(cache_key))
+            hit = _FRAGMENT_CACHE.get(k)
+            if hit and (now - hit[0]) < _FRAGMENT_TTL_SECONDS:
+                return hit[1]
+            html = templates.get_template(template_name).render(**ctx)
+            _FRAGMENT_CACHE[k] = (now, html)
+            return html
+        return templates.get_template(template_name).render(**ctx)
+    except Exception:
+        return templates.get_template(template_name).render(**ctx)
+
+templates.env.globals["render_cached"] = render_cached
+
 # --- Diagnostics: request-id and uptime ---
 _APP_START_TIME = time.time()
 
@@ -331,3 +371,11 @@ async def diagnostics_home(request: Request) -> HTMLResponse:
     if not SHOW_DIAGNOSTICS:
         raise HTTPException(status_code=404, detail="Not Found")
     return templates.TemplateResponse("diagnostics/index.html", {"request": request})
+
+
+@app.get("/diagnostics/perf", response_class=HTMLResponse)
+async def diagnostics_perf(request: Request) -> HTMLResponse:
+    """Synthetic scroll performance page (diagnostics only)."""
+    if not SHOW_DIAGNOSTICS:
+        raise HTTPException(status_code=404, detail="Not Found")
+    return templates.TemplateResponse("diagnostics/perf.html", {"request": request})

code/web/routes/decks.py

@@ -5,7 +5,7 @@ from fastapi.responses import HTMLResponse
 from pathlib import Path
 import csv
 import os
-from typing import Dict, List, Tuple
+from typing import Dict, List, Tuple, Optional
 
 from ..app import templates
 from ..services import owned_store
@@ -47,6 +47,8 @@ def _list_decks() -> list[dict]:
                 _m = payload.get('meta', {}) if isinstance(payload, dict) else {}
                 meta["commander"] = _m.get('commander') or meta.get("commander")
                 meta["tags"] = _m.get('tags') or meta.get("tags") or []
+                if _m.get('name'):
+                    meta["display"] = _m.get('name')
             except Exception:
                 pass
         # Fallback to parsing commander/themes from filename convention Commander_Themes_YYYYMMDD
@@ -213,6 +215,38 @@ def _read_csv_summary(csv_path: Path) -> Tuple[dict, Dict[str, int], Dict[str, i
     return summary, type_counts, curve_counts, type_cards
 
 
+def _read_deck_counts(csv_path: Path) -> Dict[str, int]:
+    """Read a CSV deck export and return a mapping of card name -> total count.
+
+    Falls back to zero on parse issues; ignores header case and missing columns.
+    """
+    counts: Dict[str, int] = {}
+    try:
+        with csv_path.open('r', encoding='utf-8') as f:
+            reader = csv.reader(f)
+            headers = next(reader, [])
+            name_idx = headers.index('Name') if 'Name' in headers else 0
+            count_idx = headers.index('Count') if 'Count' in headers else 1
+            for row in reader:
+                if not row:
+                    continue
+                try:
+                    name = row[name_idx]
+                except Exception:
+                    continue
+                try:
+                    cnt = int(float(row[count_idx])) if row[count_idx] else 1
+                except Exception:
+                    cnt = 1
+                name = str(name).strip()
+                if not name:
+                    continue
+                counts[name] = counts.get(name, 0) + cnt
+    except Exception:
+        pass
+    return counts
+
+
 @router.get("/", response_class=HTMLResponse)
 async def decks_index(request: Request) -> HTMLResponse:
     items = _list_decks()
@@ -243,11 +277,14 @@ async def decks_view(request: Request, name: str) -> HTMLResponse:
                     _tags = meta.get('tags') or []
                     if isinstance(_tags, list):
                         tags = [str(t) for t in _tags]
+                    display_name = meta.get('name') or ''
         except Exception:
             summary = None
+            display_name = ''
     if not summary:
         # Reconstruct minimal summary from CSV
         summary, _tc, _cc, _tcs = _read_csv_summary(p)
+        display_name = ''
     stem = p.stem
     txt_path = p.with_suffix('.txt')
     # If missing still, infer from filename stem
@@ -263,7 +300,91 @@ async def decks_view(request: Request, name: str) -> HTMLResponse:
         "summary": summary,
         "commander": commander_name,
         "tags": tags,
+        "display_name": display_name,
     "game_changers": bc.GAME_CHANGERS,
     "owned_set": {n.lower() for n in owned_store.get_names()},
     }
     return templates.TemplateResponse("decks/view.html", ctx)
+
+
+@router.get("/compare", response_class=HTMLResponse)
+async def decks_compare(request: Request, A: Optional[str] = None, B: Optional[str] = None) -> HTMLResponse:
+    """Compare two finished deck CSVs and show diffs.
+
+    Query params:
+      - A: filename of first deck (e.g., Alena_..._20250827.csv)
+      - B: filename of second deck
+    """
+    base = _deck_dir()
+    items = _list_decks()
+    # Build select options with friendly display labels
+    options: List[Dict[str, str]] = []
+    for it in items:
+        label = it.get("display") or it.get("commander") or it.get("name")
+        # Include mtime for "Latest two" selection refinement
+        mt = it.get("mtime", 0)
+        try:
+            mt_val = str(int(mt))
+        except Exception:
+            mt_val = "0"
+        options.append({"name": it.get("name"), "label": label, "mtime": mt_val})  # type: ignore[arg-type]
+
+    diffs = None
+    metaA: Dict[str, str] = {}
+    metaB: Dict[str, str] = {}
+    if A and B:
+        pA = (base / A)
+        pB = (base / B)
+        if _safe_within(base, pA) and _safe_within(base, pB) and pA.exists() and pB.exists():
+            ca = _read_deck_counts(pA)
+            cb = _read_deck_counts(pB)
+            setA = set(ca.keys())
+            setB = set(cb.keys())
+            onlyA = sorted(list(setA - setB))
+            onlyB = sorted(list(setB - setA))
+            changed: List[Tuple[str, int, int]] = []
+            for n in sorted(setA & setB):
+                if ca.get(n, 0) != cb.get(n, 0):
+                    changed.append((n, ca.get(n, 0), cb.get(n, 0)))
+            # Side meta (commander/name/tags) if available
+            def _meta_for(path: Path) -> Dict[str, str]:
+                out: Dict[str, str] = {"filename": path.name}
+                sc = path.with_suffix('.summary.json')
+                try:
+                    if sc.exists():
+                        import json as _json
+                        payload = _json.loads(sc.read_text(encoding='utf-8'))
+                        if isinstance(payload, dict):
+                            m = payload.get('meta', {}) or {}
+                            out["display"] = (m.get('name') or '')
+                            out["commander"] = (m.get('commander') or '')
+                            out["tags"] = ', '.join(m.get('tags') or [])
+                except Exception:
+                    pass
+                if not out.get("commander"):
+                    parts = path.stem.split('_')
+                    if parts:
+                        out["commander"] = parts[0]
+                return out
+            metaA = _meta_for(pA)
+            metaB = _meta_for(pB)
+            diffs = {
+                "onlyA": onlyA,
+                "onlyB": onlyB,
+                "changed": changed,
+                "A": A,
+                "B": B,
+            }
+
+    return templates.TemplateResponse(
+        "decks/compare.html",
+        {
+            "request": request,
+            "options": options,
+            "A": A or "",
+            "B": B or "",
+            "diffs": diffs,
+            "metaA": metaA,
+            "metaB": metaB,
+        },
+    )

code/web/services/orchestrator.py

@@ -781,6 +781,13 @@ def run_build(commander: str, tags: List[str], bracket: int, ideals: Dict[str, i
         except Exception as e:
             out(f"Reporting phase failed: {e}")
         try:
+            # If a custom export base is threaded via environment/session in web, we can respect env var
+            try:
+                custom_base = os.getenv('WEB_CUSTOM_EXPORT_BASE')
+                if custom_base:
+                    setattr(b, 'custom_export_base', custom_base)
+            except Exception:
+                pass
             if hasattr(b, 'export_decklist_csv'):
                 csv_path = b.export_decklist_csv()  # type: ignore[attr-defined]
         except Exception as e:
@@ -819,6 +826,13 @@ def run_build(commander: str, tags: List[str], bracket: int, ideals: Dict[str, i
                     "csv": csv_path,
                     "txt": txt_path,
                 }
+                # Attach custom deck name if provided
+                try:
+                    custom_base = getattr(b, 'custom_export_base', None)
+                except Exception:
+                    custom_base = None
+                if isinstance(custom_base, str) and custom_base.strip():
+                    meta["name"] = custom_base.strip()
                 payload = {"meta": meta, "summary": summary}
                 with open(sidecar, 'w', encoding='utf-8') as f:
                     _json.dump(payload, f, ensure_ascii=False, indent=2)
@@ -898,6 +912,8 @@ def start_build_ctx(
     use_owned_only: bool | None = None,
     prefer_owned: bool | None = None,
     owned_names: List[str] | None = None,
+    locks: List[str] | None = None,
+    custom_export_base: str | None = None,
 ) -> Dict[str, Any]:
     logs: List[str] = []
 
@@ -974,6 +990,9 @@ def start_build_ctx(
         "csv_path": None,
         "txt_path": None,
         "snapshot": None,
+    "history": [],  # list of {i, key, label, snapshot}
+        "locks": {str(n).strip().lower() for n in (locks or []) if str(n).strip()},
+    "custom_export_base": str(custom_export_base).strip() if isinstance(custom_export_base, str) and custom_export_base.strip() else None,
     }
     return ctx
 
@@ -1021,13 +1040,21 @@ def _restore_builder(b: DeckBuilder, snap: Dict[str, Any]) -> None:
     b._spell_pip_cache_dirty = bool(snap.get("_spell_pip_cache_dirty", True))
 
 
-def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = False) -> Dict[str, Any]:
+def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = False, *, replace: bool = False) -> Dict[str, Any]:
     b: DeckBuilder = ctx["builder"]
     stages: List[Dict[str, Any]] = ctx["stages"]
     logs: List[str] = ctx["logs"]
+    locks_set: set[str] = set(ctx.get("locks") or [])
 
     # If all stages done, finalize exports (interactive/manual build)
     if ctx["idx"] >= len(stages):
+        # Apply custom export base if present in context
+        try:
+            custom_base = ctx.get("custom_export_base")
+            if custom_base:
+                setattr(b, 'custom_export_base', str(custom_base))
+        except Exception:
+            pass
         if not ctx.get("csv_path") and hasattr(b, 'export_decklist_csv'):
             try:
                 ctx["csv_path"] = b.export_decklist_csv()  # type: ignore[attr-defined]
@@ -1045,6 +1072,36 @@ def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = Fal
                     pass
             except Exception as e:
                 logs.append(f"Text export failed: {e}")
+        # Final lock enforcement before finishing
+        try:
+            for lname in locks_set:
+                try:
+                    # If locked card missing, attempt to add a placeholder entry
+                    if lname not in {str(n).strip().lower() for n in getattr(b, 'card_library', {}).keys()}:
+                        # Try to find exact name in dataframes
+                        target_name = None
+                        try:
+                            df = getattr(b, '_combined_cards_df', None)
+                            if df is not None and not df.empty:
+                                row = df[df['name'].astype(str).str.lower() == lname]
+                                if not row.empty:
+                                    target_name = str(row.iloc[0]['name'])
+                        except Exception:
+                            target_name = None
+                        if target_name is None:
+                            # As fallback, use the locked name as-is (display only)
+                            target_name = lname
+                        b.card_library[target_name] = {
+                            'Count': 1,
+                            'Role': 'Locked',
+                            'SubRole': '',
+                            'AddedBy': 'Lock',
+                            'TriggerTag': '',
+                        }
+                except Exception:
+                    continue
+        except Exception:
+            pass
         # Build structured summary for UI
         summary = None
         try:
@@ -1067,6 +1124,12 @@ def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = Fal
                     "csv": ctx.get("csv_path"),
                     "txt": ctx.get("txt_path"),
                 }
+                try:
+                    custom_base = getattr(b, 'custom_export_base', None)
+                except Exception:
+                    custom_base = None
+                if isinstance(custom_base, str) and custom_base.strip():
+                    meta["name"] = custom_base.strip()
                 payload = {"meta": meta, "summary": summary}
                 with open(sidecar, 'w', encoding='utf-8') as f:
                     _json.dump(payload, f, ensure_ascii=False, indent=2)
@@ -1095,8 +1158,8 @@ def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = Fal
         label = stage["label"]
         runner_name = stage["runner_name"]
 
-        # Take snapshot before executing; for rerun, restore first if we have one
-        if rerun and ctx.get("snapshot") is not None and i == max(0, int(ctx.get("last_visible_idx", ctx["idx"]) or 1) - 1):
+        # Take snapshot before executing; for rerun with replace, restore first if we have one
+        if rerun and replace and ctx.get("snapshot") is not None and i == max(0, int(ctx.get("last_visible_idx", ctx["idx"]) or 1) - 1):
             _restore_builder(b, ctx["snapshot"])  # restore to pre-stage state
         snap_before = _snapshot_builder(b)
 
@@ -1112,6 +1175,36 @@ def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = Fal
             logs.append(f"Runner not available: {runner_name}")
         delta_log = "\n".join(logs[start_log:])
 
+        # Enforce locks immediately after the stage runs so they appear in added list
+        try:
+            for lname in locks_set:
+                try:
+                    lib_keys_lower = {str(n).strip().lower(): str(n) for n in getattr(b, 'card_library', {}).keys()}
+                    if lname not in lib_keys_lower:
+                        # Try to resolve canonical name from DF
+                        target_name = None
+                        try:
+                            df = getattr(b, '_combined_cards_df', None)
+                            if df is not None and not df.empty:
+                                row = df[df['name'].astype(str).str.lower() == lname]
+                                if not row.empty:
+                                    target_name = str(row.iloc[0]['name'])
+                        except Exception:
+                            target_name = None
+                        if target_name is None:
+                            target_name = lname
+                        b.card_library[target_name] = {
+                            'Count': 1,
+                            'Role': 'Locked',
+                            'SubRole': '',
+                            'AddedBy': 'Lock',
+                            'TriggerTag': '',
+                        }
+                except Exception:
+                    continue
+        except Exception:
+            pass
+
         # Compute added cards based on snapshot
         try:
             prev_lib = snap_before.get("card_library", {}) if isinstance(snap_before, dict) else {}
@@ -1170,6 +1263,15 @@ def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = Fal
             except Exception:
                 added_total = 0
             ctx["snapshot"] = snap_before  # snapshot for rerun
+            try:
+                (ctx.setdefault("history", [])).append({
+                    "i": i + 1,
+                    "key": stage.get("key"),
+                    "label": label,
+                    "snapshot": snap_before,
+                })
+            except Exception:
+                pass
             ctx["idx"] = i + 1
             ctx["last_visible_idx"] = i + 1
             return {
@@ -1196,6 +1298,15 @@ def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = Fal
             except Exception:
                 total_cards = None
             ctx["snapshot"] = snap_before
+            try:
+                (ctx.setdefault("history", [])).append({
+                    "i": i + 1,
+                    "key": stage.get("key"),
+                    "label": label,
+                    "snapshot": snap_before,
+                })
+            except Exception:
+                pass
             ctx["idx"] = i + 1
             ctx["last_visible_idx"] = i + 1
             return {
@@ -1210,12 +1321,19 @@ def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = Fal
                 "added_total": 0,
             }
 
-        # No cards added and not showing skipped: advance to next
+        # No cards added and not showing skipped: advance to next stage and continue loop
         i += 1
         # Continue loop to auto-advance
 
     # If we reached here, all remaining stages were no-ops; finalize exports
     ctx["idx"] = len(stages)
+    # Apply custom export base if present
+    try:
+        custom_base = ctx.get("custom_export_base")
+        if custom_base:
+            setattr(b, 'custom_export_base', str(custom_base))
+    except Exception:
+        pass
     if not ctx.get("csv_path") and hasattr(b, 'export_decklist_csv'):
         try:
             ctx["csv_path"] = b.export_decklist_csv()  # type: ignore[attr-defined]
@@ -1255,6 +1373,12 @@ def run_stage(ctx: Dict[str, Any], rerun: bool = False, show_skipped: bool = Fal
                 "csv": ctx.get("csv_path"),
                 "txt": ctx.get("txt_path"),
             }
+            try:
+                custom_base = getattr(b, 'custom_export_base', None)
+            except Exception:
+                custom_base = None
+            if isinstance(custom_base, str) and custom_base.strip():
+                meta["name"] = custom_base.strip()
             payload = {"meta": meta, "summary": summary}
             with open(sidecar, 'w', encoding='utf-8') as f:
                 _json.dump(payload, f, ensure_ascii=False, indent=2)

code/web/static/app.js

@@ -110,6 +110,13 @@
   document.addEventListener('keydown', function(e){
     if (e.target && (/input|textarea|select/i).test(e.target.tagName)) return; // don't hijack inputs
     var k = e.key.toLowerCase();
+    // If focus is inside a card tile, defer 'r'/'l' to tile-scoped handlers (Alternatives/Lock)
+    try {
+      var active = document.activeElement;
+      if (active && active.closest && active.closest('.card-tile') && (k === 'r' || k === 'l')) {
+        return;
+      }
+    } catch(_) { /* noop */ }
     if (keymap[k]){ e.preventDefault(); keymap[k](); }
   });
 
@@ -165,6 +172,7 @@
     hydrateProgress(document);
     syncShowSkipped(document);
     initCardFilters(document);
+  initVirtualization(document);
   });
 
   // Hydrate progress bars with width based on data-pct
@@ -192,8 +200,31 @@
     hydrateProgress(e.target);
     syncShowSkipped(e.target);
     initCardFilters(e.target);
+  initVirtualization(e.target);
   });
 
+  // Scroll a card-tile into view (cooperates with virtualization by re-rendering first)
+  function scrollCardIntoView(name){
+    if (!name) return;
+    try{
+      var section = document.querySelector('section');
+      var grid = section && section.querySelector('.card-grid');
+      if (!grid) return;
+      // If virtualized, force a render around the approximate match by searching stored children
+      var target = grid.querySelector('.card-tile[data-card-name="'+CSS.escape(name)+'"]');
+      if (!target) {
+        // Trigger a render update and try again
+        grid.dispatchEvent(new Event('scroll')); // noop but can refresh
+        target = grid.querySelector('.card-tile[data-card-name="'+CSS.escape(name)+'"]');
+      }
+      if (target) {
+        target.scrollIntoView({ block: 'center', behavior: 'smooth' });
+        target.focus && target.focus();
+      }
+    }catch(_){}
+  }
+  window.scrollCardIntoView = scrollCardIntoView;
+
   // --- Card grid filters, reasons, and collapsible groups ---
   function initCardFilters(root){
     var section = (root || document).querySelector('section');
@@ -368,4 +399,268 @@
     }
     document.addEventListener('keydown', onKey);
   }
+
+  // --- Lightweight virtualization (feature-flagged via data-virtualize) ---
+  function initVirtualization(root){
+    try{
+  var body = document.body || document.documentElement;
+  var DIAG = !!(body && body.getAttribute('data-diag') === '1');
+      // Global diagnostics aggregator
+      var GLOBAL = (function(){
+        if (!DIAG) return null;
+        if (window.__virtGlobal) return window.__virtGlobal;
+        var store = { grids: [], summaryEl: null };
+        function ensure(){
+          if (!store.summaryEl){
+            var el = document.createElement('div');
+            el.id = 'virt-global-diag';
+            el.style.position = 'fixed';
+            el.style.right = '8px';
+            el.style.bottom = '8px';
+            el.style.background = 'rgba(17,24,39,.85)';
+            el.style.border = '1px solid var(--border)';
+            el.style.padding = '.25rem .5rem';
+            el.style.borderRadius = '6px';
+            el.style.fontSize = '12px';
+            el.style.color = '#cbd5e1';
+            el.style.zIndex = '50';
+            el.style.boxShadow = '0 4px 12px rgba(0,0,0,.35)';
+            el.style.cursor = 'default';
+            // Hidden by default; toggle with 'v'
+            el.style.display = 'none';
+            document.body.appendChild(el);
+            store.summaryEl = el;
+          }
+          return store.summaryEl;
+        }
+        function update(){
+          var el = ensure(); if (!el) return;
+          var g = store.grids;
+          var total = 0, visible = 0, lastMs = 0;
+          for (var i=0;i<g.length;i++){
+            total += g[i].total||0;
+            visible += (g[i].end||0) - (g[i].start||0);
+            lastMs = Math.max(lastMs, g[i].lastMs||0);
+          }
+          el.textContent = 'virt sum: grids '+g.length+' • visible '+visible+'/'+total+' • last '+lastMs.toFixed ? lastMs.toFixed(1) : String(lastMs)+'ms';
+        }
+        function register(gridId, ref){
+          store.grids.push({ id: gridId, ref: ref });
+          update();
+          return {
+            set: function(stats){
+              for (var i=0;i<store.grids.length;i++){
+                if (store.grids[i].id === gridId){
+                  store.grids[i] = Object.assign({ id: gridId, ref: ref }, stats);
+                  break;
+                }
+              }
+              update();
+            },
+            toggle: function(){ var el = ensure(); el.style.display = (el.style.display === 'none' ? '' : 'none'); }
+          };
+        }
+        window.__virtGlobal = { register: register, toggle: function(){ var el = ensure(); el.style.display = (el.style.display === 'none' ? '' : 'none'); } };
+        return window.__virtGlobal;
+      })();
+      // Support card grids and other scroll containers (e.g., #owned-box)
+      var grids = (root || document).querySelectorAll('.card-grid[data-virtualize="1"], #owned-box[data-virtualize="1"]');
+      if (!grids.length) return;
+      grids.forEach(function(grid){
+        if (grid.__virtBound) return;
+        grid.__virtBound = true;
+        // Basic windowing: assumes roughly similar tile heights; uses sentinel measurements.
+        var container = grid;
+        container.style.position = container.style.position || 'relative';
+  var wrapper = document.createElement('div');
+  wrapper.className = 'virt-wrapper';
+  // Ensure wrapper itself is a grid to preserve multi-column layout inside
+  // when the container (e.g., .card-grid) is virtualized.
+  wrapper.style.display = 'grid';
+        // Move children into a fragment store (for owned, children live under UL)
+        var source = container;
+        // If this is the owned box, use the UL inside as the source list
+        var ownedGrid = container.id === 'owned-box' ? container.querySelector('#owned-grid') : null;
+        if (ownedGrid) { source = ownedGrid; }
+        var all = Array.prototype.slice.call(source.children);
+        var store = document.createElement('div');
+        store.style.display = 'none';
+        all.forEach(function(n){ store.appendChild(n); });
+        var padTop = document.createElement('div');
+        var padBottom = document.createElement('div');
+        padTop.style.height = '0px'; padBottom.style.height = '0px';
+        // For owned, keep the UL but render into it; otherwise append wrapper to container
+        if (ownedGrid){
+          ownedGrid.innerHTML = '';
+          ownedGrid.appendChild(padTop);
+          ownedGrid.appendChild(wrapper);
+          ownedGrid.appendChild(padBottom);
+          ownedGrid.appendChild(store);
+        } else {
+          container.appendChild(wrapper);
+          container.appendChild(padBottom);
+          container.appendChild(store);
+        }
+        var rowH = container.id === 'owned-box' ? 160 : 240; // estimate tile height
+        var perRow = 1;
+        // Optional diagnostics overlay
+        var diagBox = null; var lastRenderAt = 0; var lastRenderMs = 0;
+        var renderCount = 0; var measureCount = 0; var swapCount = 0;
+        var gridId = (container.id || container.className || 'grid') + '#' + Math.floor(Math.random()*1e6);
+        var globalReg = DIAG && GLOBAL ? GLOBAL.register(gridId, container) : null;
+        function fmt(n){ try{ return (Math.round(n*10)/10).toFixed(1); }catch(_){ return String(n); } }
+        function ensureDiag(){
+          if (!DIAG) return null;
+          if (diagBox) return diagBox;
+          diagBox = document.createElement('div');
+          diagBox.className = 'virt-diag';
+          diagBox.style.position = 'sticky';
+          diagBox.style.top = '0';
+          diagBox.style.zIndex = '5';
+          diagBox.style.background = 'rgba(17,24,39,.85)';
+          diagBox.style.border = '1px solid var(--border)';
+          diagBox.style.padding = '.25rem .5rem';
+          diagBox.style.borderRadius = '6px';
+          diagBox.style.fontSize = '12px';
+          diagBox.style.margin = '0 0 .35rem 0';
+          diagBox.style.color = '#cbd5e1';
+          diagBox.style.display = 'none'; // hidden until toggled
+          // Controls
+          var controls = document.createElement('div');
+          controls.style.display = 'flex';
+          controls.style.gap = '.35rem';
+          controls.style.alignItems = 'center';
+          controls.style.marginBottom = '.25rem';
+          var title = document.createElement('div'); title.textContent = 'virt diag'; title.style.fontWeight = '600'; title.style.fontSize = '11px'; title.style.color = '#9ca3af';
+          var btnCopy = document.createElement('button'); btnCopy.type = 'button'; btnCopy.textContent = 'Copy'; btnCopy.className = 'btn small';
+          btnCopy.addEventListener('click', function(){ try{ var payload = {
+            id: gridId, rowH: rowH, perRow: perRow, start: start, end: end, total: total,
+            renderCount: renderCount, measureCount: measureCount, swapCount: swapCount,
+            lastRenderMs: lastRenderMs, lastRenderAt: lastRenderAt
+          }; navigator.clipboard.writeText(JSON.stringify(payload, null, 2)); btnCopy.textContent = 'Copied'; setTimeout(function(){ btnCopy.textContent = 'Copy'; }, 1200); }catch(_){ }
+          });
+          var btnHide = document.createElement('button'); btnHide.type = 'button'; btnHide.textContent = 'Hide'; btnHide.className = 'btn small';
+          btnHide.addEventListener('click', function(){ diagBox.style.display = 'none'; });
+          controls.appendChild(title); controls.appendChild(btnCopy); controls.appendChild(btnHide);
+          diagBox.appendChild(controls);
+          var text = document.createElement('div'); text.className = 'virt-diag-text'; diagBox.appendChild(text);
+          var host = (container.id === 'owned-box') ? container : container.parentElement || container;
+          host.insertBefore(diagBox, host.firstChild);
+          return diagBox;
+        }
+        function measure(){
+          try {
+            measureCount++;
+            // create a temp tile to measure if none
+            var probe = store.firstElementChild || all[0];
+            if (probe){
+              var fake = probe.cloneNode(true);
+              fake.style.position = 'absolute'; fake.style.visibility = 'hidden'; fake.style.pointerEvents = 'none';
+              (ownedGrid || container).appendChild(fake);
+              var rect = fake.getBoundingClientRect();
+              rowH = Math.max(120, Math.ceil(rect.height) + 16);
+              (ownedGrid || container).removeChild(fake);
+            }
+            // Estimate perRow via computed styles of grid
+            var style = window.getComputedStyle(ownedGrid || container);
+            var cols = style.getPropertyValue('grid-template-columns');
+            // Mirror grid settings onto the wrapper so its children still flow in columns
+            try {
+              if (cols && cols.trim()) wrapper.style.gridTemplateColumns = cols;
+              var gap = style.getPropertyValue('gap') || style.getPropertyValue('grid-gap');
+              if (gap && gap.trim()) wrapper.style.gap = gap;
+              // Inherit justify/align if present
+              var ji = style.getPropertyValue('justify-items');
+              if (ji && ji.trim()) wrapper.style.justifyItems = ji;
+              var ai = style.getPropertyValue('align-items');
+              if (ai && ai.trim()) wrapper.style.alignItems = ai;
+            } catch(_) {}
+            perRow = Math.max(1, (cols && cols.split ? cols.split(' ').filter(function(x){return x && (x.indexOf('px')>-1 || x.indexOf('fr')>-1 || x.indexOf('minmax(')>-1);}).length : 1));
+          } catch(_){}
+        }
+        measure();
+        var total = all.length;
+        var start = 0, end = 0;
+        function render(){
+          var t0 = DIAG ? performance.now() : 0;
+          var scroller = container;
+          var vh = scroller.clientHeight || window.innerHeight;
+          var scrollTop = scroller.scrollTop;
+          // If container isn’t scrollable, use window scroll offset
+          var top = scrollTop || (scroller.getBoundingClientRect().top < 0 ? -scroller.getBoundingClientRect().top : 0);
+          var rowsInView = Math.ceil(vh / rowH) + 2; // overscan
+          var rowStart = Math.max(0, Math.floor(top / rowH) - 1);
+          var rowEnd = Math.min(Math.ceil((top / rowH)) + rowsInView, Math.ceil(total / perRow));
+          var newStart = rowStart * perRow;
+          var newEnd = Math.min(total, rowEnd * perRow);
+          if (newStart === start && newEnd === end) return; // no change
+          start = newStart; end = newEnd;
+          // Padding
+          var beforeRows = Math.floor(start / perRow);
+          var afterRows = Math.ceil((total - end) / perRow);
+          padTop.style.height = (beforeRows * rowH) + 'px';
+          padBottom.style.height = (afterRows * rowH) + 'px';
+          // Render visible children
+          wrapper.innerHTML = '';
+          for (var i = start; i < end; i++) {
+            var node = all[i];
+            if (node) wrapper.appendChild(node);
+          }
+          if (DIAG){
+            var box = ensureDiag();
+            if (box){
+              var dt = performance.now() - t0; lastRenderMs = dt; renderCount++; lastRenderAt = Date.now();
+              var vis = end - start; var rowsTotal = Math.ceil(total / perRow);
+              var textEl = box.querySelector('.virt-diag-text');
+              var msg = 'range ['+start+'..'+end+') of '+total+' • vis '+vis+' • rows ~'+rowsTotal+' • perRow '+perRow+' • rowH '+rowH+'px • render '+fmt(dt)+'ms • renders '+renderCount+' • measures '+measureCount+' • swaps '+swapCount;
+              textEl.textContent = msg;
+              // Health hint
+              var bad = (dt > 33) || (vis > 300);
+              var warn = (!bad) && ((dt > 16) || (vis > 200));
+              box.style.borderColor = bad ? '#ef4444' : (warn ? '#f59e0b' : 'var(--border)');
+              box.style.boxShadow = bad ? '0 0 0 1px rgba(239,68,68,.35)' : (warn ? '0 0 0 1px rgba(245,158,11,.25)' : 'none');
+              if (globalReg && globalReg.set){ globalReg.set({ total: total, start: start, end: end, lastMs: dt }); }
+            }
+          }
+        }
+        function onScroll(){ render(); }
+        function onResize(){ measure(); render(); }
+        container.addEventListener('scroll', onScroll);
+        window.addEventListener('resize', onResize);
+        // Initial size; ensure container is scrollable for our logic
+        if (!container.style.maxHeight) container.style.maxHeight = '70vh';
+        container.style.overflow = container.style.overflow || 'auto';
+        render();
+        // Re-render after filters resort or HTMX swaps
+        document.addEventListener('htmx:afterSwap', function(ev){ if (container.contains(ev.target)) { swapCount++; all = Array.prototype.slice.call(store.children).concat(Array.prototype.slice.call(wrapper.children)); total = all.length; measure(); render(); } });
+        // Keyboard toggle for overlays: 'v'
+        if (DIAG && !window.__virtHotkeyBound){
+          window.__virtHotkeyBound = true;
+          document.addEventListener('keydown', function(e){
+            try{
+              if (e.target && (/input|textarea|select/i).test(e.target.tagName)) return;
+              if (e.key && e.key.toLowerCase() === 'v'){
+                e.preventDefault();
+                // Toggle all virt-diag boxes and the global summary
+                var shown = null;
+                document.querySelectorAll('.virt-diag').forEach(function(b){ if (shown === null) shown = (b.style.display === 'none'); b.style.display = shown ? '' : 'none'; });
+                if (GLOBAL && GLOBAL.toggle) GLOBAL.toggle();
+              }
+            }catch(_){ }
+          });
+        }
+      });
+    }catch(_){ }
+  }
+
+  // LQIP blur/fade-in for thumbnails marked with data-lqip
+  document.addEventListener('DOMContentLoaded', function(){
+    try{
+      document.querySelectorAll('img[data-lqip]')
+        .forEach(function(img){
+          img.classList.add('lqip');
+          img.addEventListener('load', function(){ img.classList.add('loaded'); }, { once: true });
+        });
+    }catch(_){ }
+  });
 })();

code/web/static/styles.css

@@ -130,6 +130,11 @@ small, .muted{ color: var(--muted); }
 	text-align:center;
 }
 .card-tile.game-changer{ border-color: var(--red-main); box-shadow: 0 0 0 1px rgba(211,32,42,.35) inset; }
+.card-tile.locked{
+	/* Subtle yellow/goldish-white accent for locked cards */
+	border-color: #f5e6a8; /* soft parchment gold */
+	box-shadow: 0 0 0 2px rgba(245,230,168,.28) inset;
+}
 .card-tile img{ width:160px; height:auto; border-radius:6px; box-shadow: 0 6px 18px rgba(0,0,0,.35); background:#111; }
 .card-tile .name{ font-weight:600; margin-top:.25rem; font-size:.92rem; }
 .card-tile .reason{ color:var(--muted); font-size:.85rem; margin-top:.15rem; }
@@ -175,6 +180,9 @@ small, .muted{ color: var(--muted); }
 .game-changer { color: var(--green-main); }
 .stack-card.game-changer { outline: 2px solid var(--green-main); }
 
+/* Image button inside card tiles */
+.card-tile .img-btn{ display:block; padding:0; background:transparent; border:none; cursor:pointer; width:100%; }
+
 /* Stage Navigator */
 .stage-nav { margin:.5rem 0 1rem; }
 .stage-nav ol { list-style:none; padding:0; margin:0; display:flex; gap:.35rem; flex-wrap:wrap; }
@@ -221,3 +229,19 @@ small, .muted{ color: var(--muted); }
 /* Inline error banner */
 .inline-error-banner{ background:#1a0f10; border:1px solid #b91c1c; color:#fca5a5; padding:.5rem .6rem; border-radius:8px; margin-bottom:.5rem; }
 .inline-error-banner .muted{ color:#fda4af; }
+
+/* Alternatives panel */
+.alts ul{ list-style:none; padding:0; margin:0; }
+.alts li{ display:flex; align-items:center; gap:.4rem; }
+/* LQIP blur/fade-in for thumbnails */
+img.lqip { filter: blur(8px); opacity: .6; transition: filter .25s ease-out, opacity .25s ease-out; }
+img.lqip.loaded { filter: blur(0); opacity: 1; }
+
+/* Respect reduced motion: avoid blur/fade transitions for users who prefer less motion */
+@media (prefers-reduced-motion: reduce) {
+	* { scroll-behavior: auto !important; }
+	img.lqip { transition: none !important; filter: none !important; opacity: 1 !important; }
+}
+
+/* Virtualization wrapper should mirror grid to keep multi-column flow */
+.virt-wrapper { display: grid; }

code/web/templates/base.html

@@ -6,18 +6,23 @@
     <title>MTG Deckbuilder</title>
     <script src="https://unpkg.com/htmx.org@1.9.12" onerror="var s=document.createElement('script');s.src='/static/vendor/htmx-1.9.12.min.js';document.head.appendChild(s);"></script>
   <link rel="stylesheet" href="/static/styles.css?v=20250826-4" />
+  <!-- Performance hints -->
+  <link rel="preconnect" href="https://api.scryfall.com" crossorigin>
+  <link rel="dns-prefetch" href="https://api.scryfall.com">
   <!-- Favicon -->
   <link rel="icon" type="image/png" href="/static/favicon.png" />
   <link rel="shortcut icon" href="/favicon.ico" />
   <link rel="apple-touch-icon" href="/static/favicon.png" />
   </head>
-  <body>
+  <body data-diag="{% if show_diagnostics %}1{% else %}0{% endif %}" data-virt="{% if virtualize %}1{% else %}0{% endif %}">
     <header class="top-banner">
       <div class="top-inner">
         <h1>MTG Deckbuilder</h1>
         <div style="display:flex; align-items:center; gap:.5rem">
           <span id="health-dot" class="health-dot" title="Health"></span>
           <div id="banner-status" class="banner-status">{% block banner_subtitle %}{% endblock %}</div>
+          <button type="button" class="btn" style="margin-left:.5rem;" title="Open a saved permalink"
+            onclick="(function(){try{var token = prompt('Paste a /build/from?state=... URL or token:'); if(!token) return; var m = token.match(/state=([^&]+)/); var t = m? m[1] : token.trim(); if(!t) return; window.location.href = '/build/from?state=' + encodeURIComponent(t); }catch(_){}})()">Open Permalink…</button>
         </div>
       </div>
     </header>
@@ -261,7 +266,7 @@
   document.addEventListener('htmx:afterSwap', function() { attachCardHover(); bindAllCardImageRetries(); });
       })();
     </script>
-  <script src="/static/app.js?v=20250826-2"></script>
+  <script src="/static/app.js?v=20250826-4"></script>
   <script>
     // Show pending toast after full page reloads when actions replace the whole document
     (function(){

code/web/templates/build/_banner_subtitle.html

@@ -1 +1 @@
-<div id="banner-status" hx-swap-oob="true">{% if step %}<span class="muted">{{ step }}{% if i is not none and n is not none %} ({{ i }}/{{ n }}){% endif %}</span>: {% endif %}{% if commander %}<strong>{{ commander }}</strong>{% endif %}{% if tags and tags|length > 0 %} - {{ tags|join(', ') }}{% endif %}</div>
+<div id="banner-status" hx-swap-oob="true">{% if name %}<strong>{{ name }}</strong>{% elif commander %}<strong>{{ commander }}</strong>{% endif %}{% if tags and tags|length > 0 %} — {{ tags|join(', ') }}{% endif %}</div>

code/web/templates/build/_new_deck_candidates.html

@@ -0,0 +1,18 @@
+{% if candidates and candidates|length %}
+<ul style="list-style:none; padding:0; margin:.35rem 0; display:grid; gap:.25rem;" role="listbox" aria-label="Commander suggestions" tabindex="-1">
+  {% for name, score, colors in candidates %}
+  <li>
+    <button type="button" id="cand-{{ loop.index0 }}" class="chip candidate-btn" role="option" data-idx="{{ loop.index0 }}" data-name="{{ name|e }}"
+            hx-get="/build/new/inspect?name={{ name|urlencode }}"
+            hx-target="#newdeck-tags-slot" hx-swap="innerHTML"
+            hx-on="htmx:afterOnLoad: (function(){ try{ var n=this.getAttribute('data-name')||''; var ci = document.querySelector('input[name=commander]'); if(ci){ ci.value=n; try{ ci.selectionStart = ci.selectionEnd = ci.value.length; }catch(_){} } var nm = document.querySelector('input[name=name]'); if(nm && (!nm.value || !nm.value.trim())){ nm.value=n; } }catch(_){ } }).call(this)">
+      {{ name }}
+    </button>
+  </li>
+  {% endfor %}
+</ul>
+{% else %}
+  {% if query %}
+    <div class="muted">No matches for “{{ query }}”.</div>
+  {% endif %}
+{% endif %}

code/web/templates/build/_new_deck_modal.html

@@ -0,0 +1,149 @@
+<div class="modal" role="dialog" aria-modal="true" aria-labelledby="newDeckTitle" style="position:fixed; inset:0; z-index:1000; display:flex; align-items:center; justify-content:center;">
+  <div class="modal-backdrop" style="position:absolute; inset:0; background:rgba(0,0,0,.6);"></div>
+  <div class="modal-content" style="position:relative; max-width:720px; width:clamp(320px, 90vw, 720px); background:#0f1115; border:1px solid var(--border); border-radius:10px; box-shadow:0 10px 30px rgba(0,0,0,.5); padding:1rem;">
+    <div class="modal-header">
+  <h3 id="newDeckTitle">Build a New Deck</h3>
+    </div>
+    {% if error %}
+    <div class="error" role="alert" style="margin:.35rem 0 .5rem 0;">{{ error }}</div>
+    {% endif %}
+  <form hx-post="/build/new" hx-target="#wizard" hx-swap="innerHTML" hx-on="htmx:afterRequest: (function(evt){ try{ if(evt && evt.detail && evt.detail.elt === this){ var m=this.closest('.modal'); if(m){ m.remove(); } } }catch(_){} }).call(this, event)" autocomplete="off">
+      <fieldset>
+        <legend>Basics</legend>
+        <div class="basics-grid" style="display:grid; grid-template-columns: 2fr 1fr; gap:1rem; align-items:start;">
+          <div>
+            <label style="display:block; margin-bottom:.5rem;">
+              <span class="muted">Optional name (used for file names)</span>
+              <input type="text" name="name" placeholder="e.g., Inti Discard Tempo" autocomplete="off" autocapitalize="off" spellcheck="false" />
+            </label>
+            <label style="display:block; margin-bottom:.5rem;">
+              <span>Commander</span>
+    <input type="text" name="commander" required placeholder="Type a commander name" value="{{ form.commander if form else '' }}" autofocus autocomplete="off" autocapitalize="off" spellcheck="false"
+      role="combobox" aria-autocomplete="list" aria-controls="newdeck-candidates"
+      hx-get="/build/new/candidates" hx-trigger="input changed delay:150ms" hx-target="#newdeck-candidates" hx-sync="this:replace" />
+            </label>
+            <small class="muted" style="display:block; margin-top:.25rem;">Start typing to see matches, then select one to load themes.</small>
+            <div id="newdeck-candidates" class="muted" style="font-size:12px; min-height:1.1em;"></div>
+          </div>
+          <div id="newdeck-commander-slot" class="muted" style="max-width:230px;">
+            <em style="font-size:12px;">Pick a commander to preview here.</em>
+          </div>
+        </div>
+      </fieldset>
+      <fieldset>
+        <legend>Themes</legend>
+        <div id="newdeck-tags-slot" class="muted">
+          <em>Select a commander to see theme recommendations and choices.</em>
+          <input type="hidden" name="primary_tag" />
+          <input type="hidden" name="secondary_tag" />
+          <input type="hidden" name="tertiary_tag" />
+          <input type="hidden" name="tag_mode" value="AND" />
+        </div>
+        <div style="margin-top:.5rem;">
+          <label>Bracket
+            <select name="bracket">
+              {% for b in brackets %}
+              <option value="{{ b.level }}" {% if (form and form.bracket and form.bracket == b.level) or (not form and b.level == 3) %}selected{% endif %}>Bracket {{ b.level }}: {{ b.name }}</option>
+              {% endfor %}
+            </select>
+          </label>
+        </div>
+      </fieldset>
+      <details style="margin-top:.5rem;">
+        <summary>Advanced options (ideals)</summary>
+        <div style="display:grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap:.5rem; margin-top:.5rem;">
+          {% for key, label in labels.items() %}
+          <label>{{ label }}
+            <input type="number" name="{{ key }}" value="{{ defaults[key] }}" min="0" />
+          </label>
+          {% endfor %}
+        </div>
+      </details>
+      <div class="modal-footer" style="display:flex; gap:.5rem; justify-content:flex-end; margin-top:1rem;">
+        <button type="button" class="btn" onclick="this.closest('.modal').remove()">Cancel</button>
+        <button type="submit" class="btn-continue">Create</button>
+      </div>
+    </form>
+  </div>
+</div>
+
+<script>
+  (function(){
+    var modal = document.currentScript && document.currentScript.previousElementSibling ? document.currentScript.previousElementSibling.previousElementSibling : document.querySelector('.modal');
+    // Prevent Enter in text inputs from submitting the form
+    try {
+      var form = modal ? modal.querySelector('form') : document.querySelector('.modal form');
+      if (form){
+        // Prevent Enter in name field from submitting
+        var nameEl = form.querySelector('input[name="name"]');
+        if (nameEl){ nameEl.addEventListener('keydown', function(e){ if (e.key === 'Enter'){ e.preventDefault(); } }); }
+        // In commander field, Enter picks the first candidate (if any) without closing the modal
+        var cmdEl = form.querySelector('input[name=\"commander\"]');
+        if (cmdEl){
+          function handleEnterNav(e){
+            // Enter selects the highlighted (or first) suggestion
+            var list = document.getElementById('newdeck-candidates');
+            var btns = list ? Array.prototype.slice.call(list.querySelectorAll('button.candidate-btn')) : [];
+            var getActiveIndex = function(){ return btns.findIndex(function(b){ return b.classList.contains('active'); }); };
+            if (!btns.length) return; // nothing to do, but we've already prevented default
+            // Skip if a request is in-flight to avoid fighting with swap timing
+            try{ if (cmdEl.matches('.htmx-request') || list.matches('.htmx-request')) return; }catch(_){ }
+            if (e.key === 'Enter'){
+              var idx = getActiveIndex();
+              var target = btns[(idx >= 0 ? idx : 0)];
+              if (target) { target.click(); }
+            }
+          }
+          // Capture keydown early to prevent submit on Enter (arrows left to default behavior)
+          cmdEl.addEventListener('keydown', function(e){
+            if (e.key === 'Enter'){
+              var list = document.getElementById('newdeck-candidates');
+              var hasBtns = !!(list && list.querySelector('button.candidate-btn'));
+              if (hasBtns){
+                e.preventDefault();
+                e.stopPropagation();
+                handleEnterNav(e);
+              }
+            }
+          }, true);
+          // Defensive: also block Enter on keyup (in case a browser tries to submit on keyup)
+          cmdEl.addEventListener('keyup', function(e){ if (e.key === 'Enter'){ e.preventDefault(); e.stopPropagation(); } });
+      // Global fallback: capture keydown at the document level so Enter never slips through when the commander input is focused
+          document.addEventListener('keydown', function(e){
+            try{
+              if (document.activeElement !== cmdEl) return;
+        if (e.key !== 'Enter') return;
+              var list = document.getElementById('newdeck-candidates');
+              var hasBtns = !!(list && list.querySelector('button.candidate-btn'));
+              if (!hasBtns) return;
+              e.preventDefault();
+              e.stopPropagation();
+              handleEnterNav(e);
+            }catch(_){ }
+          }, true);
+          // Reset candidate highlight when the list updates
+          document.body.addEventListener('htmx:afterSwap', function(ev){
+            try {
+              var tgt = ev && ev.detail && ev.detail.target ? ev.detail.target : null;
+              if (!tgt) return;
+              if (tgt.id === 'newdeck-candidates'){
+                var first = tgt.querySelector('button.candidate-btn');
+                if (first){
+                  // Clear any lingering active classes, then set the first as active for immediate Enter selection
+                  tgt.querySelectorAll('button.candidate-btn').forEach(function(b){ b.classList.remove('active'); b.setAttribute('aria-selected','false'); });
+                  first.classList.add('active');
+                  first.setAttribute('aria-selected','true');
+                  try{ cmdEl.setAttribute('aria-activedescendant', first.id || ''); }catch(_){ }
+                }
+              }
+            } catch(_){}
+          });
+        }
+      }
+    } catch(_){ }
+    // Close on Escape
+    function closeModal(){ try{ var m = document.querySelector('.modal'); if(m){ m.remove(); document.removeEventListener('keydown', onKey); } }catch(_){} }
+    function onKey(e){ if (e.key === 'Escape'){ e.preventDefault(); closeModal(); } }
+    document.addEventListener('keydown', onKey);
+  })();
+</script>

code/web/templates/build/_new_deck_tags.html

@@ -0,0 +1,105 @@
+{% set pname = commander.name %}
+<div id="newdeck-commander-slot" hx-swap-oob="true" style="max-width:230px;">
+  <aside class="card-preview" data-card-name="{{ pname }}" style="max-width: 230px;">
+    <a href="https://scryfall.com/search?q={{ pname|urlencode }}" target="_blank" rel="noopener">
+      <img src="https://api.scryfall.com/cards/named?fuzzy={{ pname|urlencode }}&format=image&version=normal" alt="{{ pname }} card image" data-card-name="{{ pname }}" style="width:200px; height:auto; display:block; border-radius:6px;" />
+    </a>
+  </aside>
+  <div class="muted" style="font-size:12px; margin-top:.25rem; max-width: 230px;">{{ pname }}</div>
+  <script>
+    try {
+      var nm = document.querySelector('input[name="name"]');
+      var value = document.querySelector('#newdeck-commander-slot [data-card-name]')?.getAttribute('data-card-name') || '{{ pname|e }}';
+      if (nm && (!nm.value || !nm.value.trim())) { nm.value = value; }
+    } catch(_) {}
+  </script>
+</div>
+
+<div>
+  {% if tags and tags|length %}
+  <div class="muted" style="font-size:12px; margin-bottom:.35rem;">Pick up to three themes. Toggle AND/OR to control how themes combine.</div>
+  <div style="display:flex; align-items:center; gap:.5rem; flex-wrap:wrap; margin-bottom:.35rem;">
+    <span class="muted" style="font-size:12px;">Combine</span>
+    <div role="group" aria-label="Combine mode">
+      <label style="margin-right:.35rem;" title="AND prioritizes cards that match multiple of your themes (tighter synergy, smaller pool).">
+        <input type="radio" name="combine_mode_radio" value="AND" checked /> AND
+      </label>
+      <label title="OR treats your themes as a union (broader pool, fills easier).">
+        <input type="radio" name="combine_mode_radio" value="OR" /> OR
+      </label>
+    </div>
+    <button type="button" id="modal-reset-tags" class="chip" style="margin-left:.35rem;">Reset themes</button>
+    <span id="modal-tag-count" class="muted" style="font-size:12px;"></span>
+  </div>
+  {% if recommended and recommended|length %}
+  <div style="display:flex; align-items:center; gap:.5rem; margin:.25rem 0 .35rem 0;">
+    <div class="muted" style="font-size:12px;">Recommended</div>
+  </div>
+  <div id="modal-tag-reco" aria-label="Recommended themes" style="display:flex; gap:.35rem; flex-wrap:wrap; margin-bottom:.5rem;">
+    {% for r in recommended %}
+      {% set tip = (recommended_reasons[r] if (recommended_reasons is defined and recommended_reasons and recommended_reasons.get(r)) else 'Recommended for this commander') %}
+      <button type="button" class="chip chip-reco" data-tag="{{ r }}" title="{{ tip }}">★ {{ r }}</button>
+    {% endfor %}
+    <button type="button" id="modal-reco-select-all" class="chip" title="Add recommended up to 3">Select all</button>
+  </div>
+  {% endif %}
+  <div id="modal-tag-list" aria-label="Available themes" style="display:flex; gap:.35rem; flex-wrap:wrap;">
+    {% for t in tags %}
+      <button type="button" class="chip" data-tag="{{ t }}">{{ t }}</button>
+    {% endfor %}
+  </div>
+  {% else %}
+    <p class="muted">No theme tags available for this commander.</p>
+  {% endif %}
+  <!-- hidden inputs that the main modal form will submit -->
+  <input type="hidden" name="primary_tag" id="modal_primary_tag" />
+  <input type="hidden" name="secondary_tag" id="modal_secondary_tag" />
+  <input type="hidden" name="tertiary_tag" id="modal_tertiary_tag" />
+  <input type="hidden" name="tag_mode" id="modal_tag_mode" value="AND" />
+
+  <div id="modal-selected-themes" class="muted" style="font-size:12px; margin-top:.5rem;">
+    <em>No themes selected yet.</em>
+  </div>
+</div>
+
+<script>
+(function(){
+  var list = document.getElementById('modal-tag-list');
+  var reco = document.getElementById('modal-tag-reco');
+  var selAll = document.getElementById('modal-reco-select-all');
+  var resetBtn = document.getElementById('modal-reset-tags');
+  var p = document.getElementById('modal_primary_tag');
+  var s = document.getElementById('modal_secondary_tag');
+  var t = document.getElementById('modal_tertiary_tag');
+  var mode = document.getElementById('modal_tag_mode');
+  var countEl = document.getElementById('modal-tag-count');
+  var selSummary = document.getElementById('modal-selected-themes');
+  if (!list) return;
+
+  function getSel(){ var a=[]; if(p&&p.value)a.push(p.value); if(s&&s.value)a.push(s.value); if(t&&t.value)a.push(t.value); return a; }
+  function setSel(a){ a = Array.from(new Set(a||[])).filter(Boolean).slice(0,3); if(p) p.value=a[0]||''; if(s) s.value=a[1]||''; if(t) t.value=a[2]||''; updateUI(); }
+  function toggle(tag){ var cur=getSel(); var i=cur.indexOf(tag); if(i>=0){cur.splice(i,1);} else { if(cur.length>=3){cur=cur.slice(1);} cur.push(tag);} setSel(cur); }
+  function updateUI(){
+    try{ if(countEl) countEl.textContent = getSel().length + ' / 3 selected'; }catch(_){ }
+    try{
+      if(selSummary){
+        var sel = getSel();
+        if(!sel.length){ selSummary.innerHTML = '<em>No themes selected yet.</em>'; }
+        else {
+          var parts = [];
+          sel.forEach(function(tag, idx){ parts.push((idx+1) + '. ' + tag); });
+          selSummary.textContent = 'Selected: ' + parts.join('  ·  ');
+        }
+      }
+    }catch(_){ }
+    function apply(container){ if(!container) return; var chips = container.querySelectorAll('button.chip'); chips.forEach(function(btn){ var tag=btn.dataset.tag||''; var active=getSel().indexOf(tag)>=0; btn.classList.toggle('active', active); btn.setAttribute('aria-pressed', active?'true':'false'); }); }
+    apply(list); apply(reco);
+  }
+  if (resetBtn) resetBtn.addEventListener('click', function(){ setSel([]); });
+  list.querySelectorAll('button.chip').forEach(function(btn){ var tag=btn.dataset.tag||''; btn.addEventListener('click', function(){ toggle(tag); }); });
+  if (reco){ reco.querySelectorAll('button.chip-reco').forEach(function(btn){ var tag=btn.dataset.tag||''; btn.addEventListener('click', function(){ toggle(tag); }); }); }
+  if (selAll){ selAll.addEventListener('click', function(){ try{ var cur=getSel(); var recs = reco? Array.from(reco.querySelectorAll('button.chip-reco')).map(function(b){return b.dataset.tag||'';}).filter(Boolean):[]; var combined=cur.slice(); recs.forEach(function(x){ if(combined.indexOf(x)===-1) combined.push(x); }); setSel(combined.slice(-3)); }catch(_){} }); }
+  document.querySelectorAll('input[name="combine_mode_radio"]').forEach(function(r){ r.addEventListener('change', function(){ if(mode){ mode.value = r.value; } }); });
+  updateUI();
+})();
+</script>

code/web/templates/build/_step2.html

@@ -1,6 +1,5 @@
 <section>
-  {% set step_index = 2 %}{% set step_total = 5 %}
-  <h3>Step 2: Tags & Bracket</h3>
+  {# Step phases removed #}
   <div class="two-col two-col-left-rail">
   <aside class="card-preview" data-card-name="{{ commander.name }}">
       <a href="https://scryfall.com/search?q={{ commander.name|urlencode }}" target="_blank" rel="noopener">
@@ -8,8 +7,7 @@
       </a>
     </aside>
     <div class="grow" data-skeleton>
-  {% include "build/_stage_navigator.html" %}
-  <div hx-get="/build/banner?step=Tags%20%26%20Bracket&i=2&n=5" hx-trigger="load"></div>
+  <div hx-get="/build/banner" hx-trigger="load"></div>
 
       <form hx-post="/build/step2" hx-target="#wizard" hx-swap="innerHTML">
         <input type="hidden" name="commander" value="{{ commander.name }}" />
@@ -95,7 +93,7 @@
       </form>
 
       <div style="margin-top:.5rem;">
-        <form action="/build" method="get" style="display:inline; margin:0;">
+        <form hx-post="/build/reset-all" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; margin:0;">
           <button type="submit">Start over</button>
         </form>
       </div>
@@ -116,6 +114,7 @@
     var countEl = document.getElementById('tag-count');
   var orderEl = document.getElementById('tag-order');
   var commander = '{{ commander.name|e }}';
+  var clearPersisted = '{{ (clear_persisted|default(false)) and "1" or "0" }}' === '1';
     if (!chipHost) return;
 
     function storageKey(suffix){ return 'step2-' + (commander || 'unknown') + '-' + suffix; }
@@ -158,6 +157,13 @@
     }
     function loadPersisted(){
       try {
+        // If this page load follows a fresh commander confirmation, wipe persisted values.
+        if (clearPersisted){
+          try {
+            localStorage.removeItem(storageKey('tags'));
+            localStorage.removeItem(storageKey('mode'));
+          } catch(_){ }
+        }
         var savedTags = JSON.parse(localStorage.getItem(storageKey('tags')) || '[]');
         var savedMode = localStorage.getItem(storageKey('mode')) || (tagMode && tagMode.value) || 'AND';
         if ((!primary.value && !secondary.value && !tertiary.value) && Array.isArray(savedTags) && savedTags.length){ setSelected(savedTags); }

code/web/templates/build/_step3.html

@@ -1,6 +1,5 @@
 <section>
-  {% set step_index = 3 %}{% set step_total = 5 %}
-  <h3>Step 3: Ideal Counts</h3>
+  {# Step phases removed #}
   <div class="two-col two-col-left-rail">
   <aside class="card-preview" data-card-name="{{ commander|urlencode }}">
       <a href="https://scryfall.com/search?q={{ commander|urlencode }}" target="_blank" rel="noopener">
@@ -8,8 +7,7 @@
       </a>
     </aside>
     <div class="grow" data-skeleton>
-      <div hx-get="/build/banner?step=Ideal%20Counts&i=3&n=5" hx-trigger="load"></div>
-      {% include "build/_stage_navigator.html" %}
+  <div hx-get="/build/banner" hx-trigger="load"></div>
 
       
 
@@ -37,7 +35,7 @@
         </div>
       </form>
       <div style="margin-top:.5rem;">
-        <form action="/build" method="get" style="display:inline; margin:0;">
+        <form hx-post="/build/reset-all" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; margin:0;">
           <button type="submit">Start over</button>
         </form>
       </div>

code/web/templates/build/_step4.html

@@ -1,6 +1,5 @@
 <section>
-	{% set step_index = 4 %}{% set step_total = 5 %}
-	<h3>Step 4: Review</h3>
+	{# Step phases removed #}
 	<div class="two-col two-col-left-rail">
 	<aside class="card-preview" data-card-name="{{ commander|urlencode }}">
 			<a href="https://scryfall.com/search?q={{ commander|urlencode }}" target="_blank" rel="noopener">
@@ -8,8 +7,12 @@
 			</a>
 		</aside>
 		<div class="grow" data-skeleton>
-			<div hx-get="/build/banner?step=Review&i=4&n=5" hx-trigger="load"></div>
-			{% include "build/_stage_navigator.html" %}
+			<div hx-get="/build/banner" hx-trigger="load"></div>
+			{% if locks_restored and locks_restored > 0 %}
+			  <div class="muted" style="margin:.35rem 0;">
+			    <span class="chip" title="Locks restored from permalink">🔒 {{ locks_restored }} locks restored</span>
+			  </div>
+			{% endif %}
 			<h4>Chosen Ideals</h4>
 			<ul>
 				{% for key, label in labels.items() %}
@@ -27,12 +30,13 @@
 				</label>
 				<a href="/owned" target="_blank" rel="noopener" class="btn">Manage Owned Library</a>
 			</form>
+			<div class="muted" style="font-size:12px; margin-top:-.25rem;">Tip: Locked cards are respected on reruns in Step 5.</div>
 							<div style="margin-top:1rem; display:flex; gap:.5rem;">
 								<form action="/build/step5/start" method="post" hx-post="/build/step5/start" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; margin:0;">
 									<button type="submit" class="btn-continue" data-action="continue">Build Deck</button>
 								</form>
 								<button type="button" class="btn-back" data-action="back" hx-get="/build/step3" hx-target="#wizard" hx-swap="innerHTML">Back</button>
-								<form action="/build" method="get" style="display:inline; margin:0;">
+								<form hx-post="/build/reset-all" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; margin:0;">
 									<button type="submit">Start over</button>
 								</form>
 							</div>

code/web/templates/build/_step5.html

@@ -1,10 +1,11 @@
 <section>
-  {% set step_index = 5 %}{% set step_total = 5 %}
-  <h3>Step 5: Build</h3>
+  {# Step phases removed #}
   <div class="two-col two-col-left-rail">
     <aside class="card-preview">
     <a href="https://scryfall.com/search?q={{ commander|urlencode }}" target="_blank" rel="noopener">
-  <img src="https://api.scryfall.com/cards/named?fuzzy={{ commander|urlencode }}&format=image&version=normal" alt="{{ commander }} card image" data-card-name="{{ commander }}" />
+  <img src="https://api.scryfall.com/cards/named?fuzzy={{ commander|urlencode }}&format=image&version=normal" alt="{{ commander }} card image" data-card-name="{{ commander }}" loading="lazy" decoding="async" data-lqip="1"
+     srcset="https://api.scryfall.com/cards/named?fuzzy={{ commander|urlencode }}&format=image&version=small 160w, https://api.scryfall.com/cards/named?fuzzy={{ commander|urlencode }}&format=image&version=normal 488w, https://api.scryfall.com/cards/named?fuzzy={{ commander|urlencode }}&format=image&version=large 672w"
+     sizes="(max-width: 900px) 100vw, 320px" />
       </a>
       {% if status and status.startswith('Build complete') %}
       <div style="margin-top:.75rem; display:flex; gap:.35rem; flex-wrap:wrap;">
@@ -24,8 +25,7 @@
       {% endif %}
     </aside>
     <div class="grow" data-skeleton>
-      <div hx-get="/build/banner?step=Build&i=5&n=5" hx-trigger="load"></div>
-      {% include "build/_stage_navigator.html" %}
+  <div hx-get="/build/banner" hx-trigger="load"></div>
 
       <p>Commander: <strong>{{ commander }}</strong></p>
       <p>Tags: {{ tags|default([])|join(', ') }}</p>
@@ -48,6 +48,10 @@
   {% if added_total is not none %}
   <span class="chip"><span class="dot" style="background: var(--blue-main);"></span> Added {{ added_total }}</span>
   {% endif %}
+  <span id="locks-chip">{% if locks and locks|length > 0 %}<span class="chip" title="Locked cards">🔒 {{ locks|length }} locked</span>{% endif %}</span>
+  <button type="button" class="btn" style="margin-left:auto;" title="Copy permalink"
+      onclick="(async()=>{try{const r=await fetch('/build/permalink');const j=await r.json();const url=(j.permalink?location.origin+j.permalink:location.href+'#'+btoa(JSON.stringify(j.state||{}))); await navigator.clipboard.writeText(url); toast && toast('Permalink copied');}catch(e){alert('Copied state to console'); console.log(e);}})()">Copy Permalink</button>
+  <button type="button" class="btn" title="Open a saved permalink" onclick="(function(){try{var token = prompt('Paste a /build/from?state=... URL or token:'); if(!token) return; var m = token.match(/state=([^&]+)/); var t = m? m[1] : token.trim(); if(!t) return; window.location.href = '/build/from?state=' + encodeURIComponent(t); }catch(_){}})()">Open Permalink…</button>
       </div>
       {% set pct = ((deck_count / 100.0) * 100.0) if deck_count else 0 %}
       {% set pct_clamped = (pct if pct <= 100 else 100) %}
@@ -62,6 +66,30 @@
       </div>
       {% endif %}
 
+      {% if locked_cards is defined and locked_cards %}
+      <details id="locked-section" style="margin-top:.5rem;">
+        <summary>Locked cards (always kept)</summary>
+        <ul id="locked-list" style="list-style:none; padding:0; margin:.35rem 0 0; display:grid; gap:.35rem;">
+          {% for lk in locked_cards %}
+          <li style="display:flex; align-items:center; gap:.5rem; flex-wrap:wrap;">
+            <span class="chip"><span class="dot"></span> {{ lk.name }}</span>
+            <span class="muted">{% if lk.owned %}✔ Owned{% else %}✖ Not owned{% endif %}</span>
+            {% if lk.in_deck %}<span class="muted">• In deck</span>{% else %}<span class="muted">• Will be included on rerun</span>{% endif %}
+            <form hx-post="/build/lock" hx-target="closest li" hx-swap="outerHTML" onsubmit="try{toast('Unlocked {{ lk.name }}');}catch(_){}" style="display:inline; margin-left:auto;">
+              <input type="hidden" name="name" value="{{ lk.name }}" />
+              <input type="hidden" name="locked" value="0" />
+              <input type="hidden" name="from_list" value="1" />
+              <button type="submit" class="btn" title="Unlock" aria-pressed="true">Unlock</button>
+            </form>
+          </li>
+          {% endfor %}
+        </ul>
+      </details>
+      {% endif %}
+
+  <!-- Last action chip (oob-updated) -->
+  <div id="last-action" aria-live="polite" style="margin:.25rem 0; min-height:1.5rem;"></div>
+
   <!-- Filters toolbar -->
       <div class="cards-toolbar">
         <input type="text" name="filter_query" placeholder="Filter by name, role, or tag" data-pref="cards:filter_q" />
@@ -94,9 +122,9 @@
 
   <!-- Sticky build controls on mobile -->
       <div class="build-controls" style="position:sticky; top:0; z-index:5; background:linear-gradient(180deg, rgba(15,17,21,.95), rgba(15,17,21,.85)); border:1px solid var(--border); border-radius:10px; padding:.5rem; margin-top:1rem; display:flex; gap:.5rem; flex-wrap:wrap; align-items:center;">
-        <form hx-post="/build/step5/start" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; margin-right:.5rem; display:flex; align-items:center; gap:.5rem;" onsubmit="try{ toast('Starting build…'); }catch(_){}">
+        <form hx-post="/build/step5/start" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; margin-right:.5rem; display:flex; align-items:center; gap:.5rem;" onsubmit="try{ toast('Restarting build…'); }catch(_){}">
           <input type="hidden" name="show_skipped" value="{{ '1' if show_skipped else '0' }}" />
-          <button type="submit" class="btn-continue" data-action="continue">Start Build</button>
+          <button type="submit" class="btn-continue" data-action="continue">Restart Build</button>
         </form>
         <form hx-post="/build/step5/continue" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; display:flex; align-items:center; gap:.5rem;" onsubmit="try{ toast('Continuing…'); }catch(_){}">
           <input type="hidden" name="show_skipped" value="{{ '1' if show_skipped else '0' }}" />
@@ -106,6 +134,23 @@
           <input type="hidden" name="show_skipped" value="{{ '1' if show_skipped else '0' }}" />
           <button type="submit" class="btn-rerun" data-action="rerun" {% if status and status.startswith('Build complete') %}disabled{% endif %}>Rerun Stage</button>
         </form>
+        <span class="sep"></span>
+    <div class="replace-toggle" role="group" aria-label="Replace toggle">
+          <form hx-post="/build/step5/toggle-replace" hx-target="closest .replace-toggle" hx-swap="outerHTML" onsubmit="return false;" style="display:inline;">
+            <input type="hidden" name="replace" value="{{ '1' if replace_mode else '0' }}" />
+      <label class="muted" style="display:flex; align-items:center; gap:.35rem;" title="When enabled, reruns of this stage will replace its picks with alternatives instead of keeping them.">
+              <input type="checkbox" name="replace_chk" value="1" {% if replace_mode %}checked{% endif %}
+                onchange="try{ const f=this.form; const h=f.querySelector('input[name=replace]'); if(h){ h.value=this.checked?'1':'0'; } f.requestSubmit(); }catch(_){ }" />
+              Replace stage picks
+            </label>
+          </form>
+        </div>
+        <form hx-post="/build/step5/reset-stage" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; display:flex; align-items:center; gap:.5rem;">
+          <button type="submit" class="btn" title="Reset this stage to pre-stage picks">Reset stage</button>
+        </form>
+        <form hx-post="/build/reset-all" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; display:flex; align-items:center; gap:.5rem;">
+          <button type="submit" class="btn" title="Start a brand new build (clears selections)">New build</button>
+        </form>
         <label class="muted" style="display:flex; align-items:center; gap:.35rem; margin-left: .5rem;">
           <input type="checkbox" name="__toggle_show_skipped" data-pref="build:show_skipped" {% if show_skipped %}checked{% endif %}
                  onchange="const val=this.checked?'1':'0'; for(const f of this.closest('section').querySelectorAll('form')){ const h=f.querySelector('input[name=show_skipped]'); if(h) h.value=val; }" />
@@ -115,6 +160,23 @@
       </div>
 
       {% if added_cards is not none %}
+      {% if history is defined and history %}
+      <details style="margin-top:.5rem;">
+        <summary>Stage timeline</summary>
+        <div class="muted" style="font-size:12px; margin:.25rem 0 .35rem 0;">Jump back to a previous stage, then you can continue forward again.</div>
+        <ul style="list-style:none; padding:0; margin:0; display:grid; gap:.25rem;">
+          {% for h in history %}
+          <li style="display:flex; align-items:center; gap:.5rem;">
+            <span class="chip"><span class="dot"></span> {{ h.label }}</span>
+            <form hx-post="/build/step5/rewind" hx-target="#wizard" hx-swap="innerHTML" style="display:inline; margin:0;">
+              <input type="hidden" name="to" value="{{ h.i }}" />
+              <button type="submit" class="btn">Go</button>
+            </form>
+          </li>
+          {% endfor %}
+        </ul>
+      </details>
+      {% endif %}
   <h4 style="margin-top:1rem;">Cards added this stage</h4>
       {% if skipped and (not added_cards or added_cards|length == 0) %}
         <div class="muted" style="margin:.25rem 0 .5rem 0;">No cards added in this stage.</div>
@@ -127,6 +189,7 @@
   {% if stage_label and stage_label.startswith('Creatures') %}
         {% set groups = added_cards|groupby('sub_role') %}
         {% for g in groups %}
+          {% set group_idx = loop.index0 %}
           {% set role = g.grouper %}
           {% if role %}
             {% set heading = 'Theme: ' + role.title() %}
@@ -139,46 +202,81 @@
               <span class="count">(<span data-count>{{ g.list|length }}</span>)</span>
               <button type="button" class="toggle" title="Collapse/Expand">Toggle</button>
             </div>
-            <div class="card-grid group-grid" data-skeleton>
+  <div class="card-grid group-grid" data-skeleton {% if virtualize %}data-virtualize="1"{% endif %}>
       {% for c in g.list %}
             {% set owned = (owned_set is defined and c.name and (c.name|lower in owned_set)) %}
-            <div class="card-tile{% if game_changers and (c.name in game_changers) %} game-changer{% endif %}" data-card-name="{{ c.name }}" data-role="{{ c.role or c.sub_role or '' }}" data-tags="{{ (c.tags|join(', ')) if c.tags else '' }}" data-owned="{{ '1' if owned else '0' }}">
-              <a href="https://scryfall.com/search?q={{ c.name|urlencode }}" target="_blank" rel="noopener">
-                <img src="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal" alt="{{ c.name }} image" width="160" data-card-name="{{ c.name }}" />
-              </a>
+            {% set is_locked = (locks is defined and (c.name|lower in locks)) %}
+            <div class="card-tile{% if game_changers and (c.name in game_changers) %} game-changer{% endif %}{% if is_locked %} locked{% endif %}" data-card-name="{{ c.name }}" data-role="{{ c.role or c.sub_role or '' }}" data-tags="{{ (c.tags|join(', ')) if c.tags else '' }}" data-owned="{{ '1' if owned else '0' }}">
+  <button type="button" class="img-btn" title="{{ 'Unlock this card (kept across reruns)' if is_locked else 'Lock this card (keep across reruns)' }}" aria-pressed="{{ 'true' if is_locked else 'false' }}"
+          hx-post="/build/lock" hx-target="#lock-{{ group_idx }}-{{ loop.index0 }}" hx-swap="innerHTML"
+          hx-vals='{"name": "{{ c.name }}", "locked": "{{ '0' if is_locked else '1' }}"}'
+          hx-on="htmx:afterOnLoad: (function(){try{const tile=this.closest('.card-tile');if(!tile)return;const valsAttr=this.getAttribute('hx-vals')||'{}';const sent=JSON.parse(valsAttr.replace(/&quot;/g,'\"'));const nowLocked=(sent.locked==='1');tile.classList.toggle('locked', nowLocked);const next=(nowLocked?'0':'1');this.setAttribute('hx-vals', JSON.stringify({name: sent.name, locked: next}));}catch(e){}})()">
+                <img class="card-thumb" src="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal" alt="{{ c.name }} image" width="160" data-card-name="{{ c.name }}" loading="lazy" decoding="async" data-lqip="1"
+                  srcset="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=small 160w, https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal 488w, https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=large 672w"
+                  sizes="160px" />
+              </button>
               <div class="owned-badge" title="{{ 'Owned' if owned else 'Not owned' }}" aria-label="{{ 'Owned' if owned else 'Not owned' }}">{% if owned %}✔{% else %}✖{% endif %}</div>
               <div class="name">{{ c.name }}{% if c.count and c.count > 1 %} ×{{ c.count }}{% endif %}</div>
+    <div class="lock-box" id="lock-{{ group_idx }}-{{ loop.index0 }}" style="display:flex; justify-content:center; gap:.25rem; margin-top:.25rem;">
+  <button type="button" class="btn-lock" title="{{ 'Unlock this card (kept across reruns)' if is_locked else 'Lock this card (keep across reruns)' }}" aria-pressed="{{ 'true' if is_locked else 'false' }}"
+      hx-post="/build/lock" hx-target="closest .lock-box" hx-swap="innerHTML"
+                        hx-vals='{"name": "{{ c.name }}", "locked": "{{ '0' if is_locked else '1' }}"}'>{{ '🔒 Unlock' if is_locked else '🔓 Lock' }}</button>
+              </div>
               {% if c.reason %}
-                <div style="display:flex; justify-content:center; margin-top:.25rem;">
+                <div style="display:flex; justify-content:center; margin-top:.25rem; gap:.35rem; flex-wrap:wrap;">
                   <button type="button" class="btn-why" aria-expanded="false">Why?</button>
+                  <button type="button" class="btn" hx-get="/build/alternatives" hx-vals='{"name": "{{ c.name }}"}' hx-target="#alts-{{ group_idx }}-{{ loop.index0 }}" hx-swap="innerHTML" title="Suggest alternatives">Alternatives</button>
                 </div>
                 <div class="reason" role="region" aria-label="Reason">{{ c.reason }}</div>
+              {% else %}
+                <div style="display:flex; justify-content:center; margin-top:.25rem;">
+                  <button type="button" class="btn" hx-get="/build/alternatives" hx-vals='{"name": "{{ c.name }}"}' hx-target="#alts-{{ group_idx }}-{{ loop.index0 }}" hx-swap="innerHTML" title="Suggest alternatives">Alternatives</button>
+                </div>
               {% endif %}
+              <div id="alts-{{ group_idx }}-{{ loop.index0 }}" class="alts" style="margin-top:.25rem;"></div>
             </div>
             {% endfor %}
             </div>
           </div>
         {% endfor %}
       {% else %}
-  <div class="card-grid" data-skeleton>
+  <div class="card-grid" data-skeleton {% if virtualize %}data-virtualize="1"{% endif %}>
           {% for c in added_cards %}
           {% set owned = (owned_set is defined and c.name and (c.name|lower in owned_set)) %}
-          <div class="card-tile{% if game_changers and (c.name in game_changers) %} game-changer{% endif %}" data-card-name="{{ c.name }}" data-role="{{ c.role or c.sub_role or '' }}" data-tags="{{ (c.tags|join(', ')) if c.tags else '' }}" data-owned="{{ '1' if owned else '0' }}">
-            <a href="https://scryfall.com/search?q={{ c.name|urlencode }}" target="_blank" rel="noopener">
-              <img src="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal" alt="{{ c.name }} image" width="160" data-card-name="{{ c.name }}" />
-            </a>
+          {% set is_locked = (locks is defined and (c.name|lower in locks)) %}
+          <div class="card-tile{% if game_changers and (c.name in game_changers) %} game-changer{% endif %}{% if is_locked %} locked{% endif %}" data-card-name="{{ c.name }}" data-role="{{ c.role or c.sub_role or '' }}" data-tags="{{ (c.tags|join(', ')) if c.tags else '' }}" data-owned="{{ '1' if owned else '0' }}">
+  <button type="button" class="img-btn" title="{{ 'Unlock this card (kept across reruns)' if is_locked else 'Lock this card (keep across reruns)' }}" aria-pressed="{{ 'true' if is_locked else 'false' }}"
+        hx-post="/build/lock" hx-target="#lock-{{ loop.index0 }}" hx-swap="innerHTML"
+        hx-vals='{"name": "{{ c.name }}", "locked": "{{ '0' if is_locked else '1' }}"}'
+        hx-on="htmx:afterOnLoad: (function(){try{const tile=this.closest('.card-tile');if(!tile)return;const valsAttr=this.getAttribute('hx-vals')||'{}';const sent=JSON.parse(valsAttr.replace(/&quot;/g,'\"'));const nowLocked=(sent.locked==='1');tile.classList.toggle('locked', nowLocked);const next=(nowLocked?'0':'1');this.setAttribute('hx-vals', JSON.stringify({name: sent.name, locked: next}));}catch(e){}})()">
+              <img class="card-thumb" src="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal" alt="{{ c.name }} image" width="160" data-card-name="{{ c.name }}" loading="lazy" decoding="async" data-lqip="1"
+                srcset="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=small 160w, https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal 488w, https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=large 672w"
+                sizes="160px" />
+            </button>
             <div class="owned-badge" title="{{ 'Owned' if owned else 'Not owned' }}" aria-label="{{ 'Owned' if owned else 'Not owned' }}">{% if owned %}✔{% else %}✖{% endif %}</div>
             <div class="name">{{ c.name }}{% if c.count and c.count > 1 %} ×{{ c.count }}{% endif %}</div>
+    <div class="lock-box" id="lock-{{ loop.index0 }}" style="display:flex; justify-content:center; gap:.25rem; margin-top:.25rem;">
+  <button type="button" class="btn-lock" title="{{ 'Unlock this card (kept across reruns)' if is_locked else 'Lock this card (keep across reruns)' }}" aria-pressed="{{ 'true' if is_locked else 'false' }}"
+          hx-post="/build/lock" hx-target="closest .lock-box" hx-swap="innerHTML"
+                      hx-vals='{"name": "{{ c.name }}", "locked": "{{ '0' if is_locked else '1' }}"}'>{{ '🔒 Unlock' if is_locked else '🔓 Lock' }}</button>
+            </div>
             {% if c.reason %}
-              <div style="display:flex; justify-content:center; margin-top:.25rem;">
+              <div style="display:flex; justify-content:center; margin-top:.25rem; gap:.35rem; flex-wrap:wrap;">
                 <button type="button" class="btn-why" aria-expanded="false">Why?</button>
+                <button type="button" class="btn" hx-get="/build/alternatives" hx-vals='{"name": "{{ c.name }}"}' hx-target="#alts-{{ loop.index0 }}" hx-swap="innerHTML" title="Suggest alternatives">Alternatives</button>
               </div>
               <div class="reason" role="region" aria-label="Reason">{{ c.reason }}</div>
+            {% else %}
+              <div style="display:flex; justify-content:center; margin-top:.25rem;">
+                <button type="button" class="btn" hx-get="/build/alternatives" hx-vals='{"name": "{{ c.name }}"}' hx-target="#alts-{{ loop.index0 }}" hx-swap="innerHTML" title="Suggest alternatives">Alternatives</button>
+              </div>
             {% endif %}
+            <div id="alts-{{ loop.index0 }}" class="alts" style="margin-top:.25rem;"></div>
           </div>
           {% endfor %}
         </div>
       {% endif %}
+  <div class="muted" style="font-size:12px; margin:.35rem 0 .25rem 0;">Tip: Click a card to lock or unlock it. Locked cards are kept across reruns and won’t be replaced unless you unlock them.</div>
       <div data-empty hidden role="status" aria-live="polite" class="muted" style="margin:.5rem 0 0;">
         No cards match your filters.
       </div>
@@ -201,3 +299,67 @@
     </div>
   </div>
 </section>
+<script>
+// Sync tile class and image-button toggle after lock button swaps
+document.addEventListener('htmx:afterSwap', function(ev){
+  try{
+    const tgt = ev.target;
+    if(!tgt) return;
+    // Only act for lock-box updates
+    if(!tgt.classList || !tgt.classList.contains('lock-box')) return;
+    const tile = tgt.closest('.card-tile');
+    if(!tile) return;
+    const lockBtn = tgt.querySelector('.btn-lock');
+    if(lockBtn){
+      const isLocked = (lockBtn.getAttribute('data-locked') === '1');
+  tile.classList.toggle('locked', isLocked);
+      const imgBtn = tile.querySelector('.img-btn');
+      if(imgBtn){
+        try{
+          const valsAttr = imgBtn.getAttribute('hx-vals') || '{}';
+          const cur = JSON.parse(valsAttr.replace(/&quot;/g, '"'));
+          const next = isLocked ? '0' : '1';
+          // Keep name stable; fallback to tile data attribute
+          const nm = cur.name || tile.getAttribute('data-card-name') || '';
+          imgBtn.setAttribute('hx-vals', JSON.stringify({ name: nm, locked: next }));
+          imgBtn.title = 'Click to ' + (isLocked ? 'unlock' : 'lock') + ' this card';
+          try { imgBtn.setAttribute('aria-pressed', isLocked ? 'true' : 'false'); } catch(_){ }
+        }catch(_){/* noop */}
+      }
+    }
+  }catch(_){/* noop */}
+});
+// Allow dismissing/auto-clearing the last-action chip
+document.addEventListener('click', function(ev){
+  try{
+    var t = ev.target;
+    if (!t) return;
+    if (t.matches && t.matches('#last-action .chip')){
+      var c = document.getElementById('last-action');
+      if (c) c.innerHTML = '';
+    }
+  }catch(_){/* noop */}
+});
+setTimeout(function(){ try{ var c=document.getElementById('last-action'); if(c && c.firstElementChild){ c.innerHTML=''; } }catch(_){} }, 6000);
+
+// Keyboard helpers: when a card-tile is focused, L toggles lock, R opens alternatives
+document.addEventListener('keydown', function(e){
+  try{
+    if (e.ctrlKey || e.metaKey || e.altKey) return;
+    var tag = (e.target && e.target.tagName) ? e.target.tagName.toLowerCase() : '';
+    // Ignore when typing in inputs/selects
+    if (tag === 'input' || tag === 'textarea' || tag === 'select') return;
+    var tile = document.activeElement && document.activeElement.closest ? document.activeElement.closest('.card-tile') : null;
+    if (!tile) return;
+    if (e.key === 'l' || e.key === 'L') {
+      e.preventDefault(); e.stopPropagation();
+      var lockFormBtn = tile.querySelector('.lock-box .btn-lock');
+      if (lockFormBtn) { lockFormBtn.click(); }
+    } else if (e.key === 'r' || e.key === 'R') {
+      e.preventDefault(); e.stopPropagation();
+      var altBtn = tile.querySelector('button[hx-get="/build/alternatives"]');
+      if (altBtn) { altBtn.click(); }
+    }
+  }catch(_){ }
+});
+</script>

code/web/templates/build/index.html

@@ -2,24 +2,12 @@
 {% block banner_subtitle %}Build a Deck{% endblock %}
 {% block content %}
 <h2>Build a Deck</h2>
+<div style="margin:.25rem 0 1rem 0;">
+  <button type="button" class="btn" hx-get="/build/new" hx-target="body" hx-swap="beforeend">Build a New Deck…</button>
+  <span class="muted" style="margin-left:.5rem;">Quick-start wizard (name, commander, themes, ideals)</span>
+  </div>
 <div id="wizard">
-  {% set step = last_step or 1 %}
-  {% if step == 1 %}
-    <div hx-get="/build/step1" hx-trigger="load" hx-target="#wizard" hx-swap="innerHTML"></div>
-    <div hx-get="/build/banner?step=Build%20a%20Deck&i=1&n=5" hx-trigger="load"></div>
-  {% elif step == 2 %}
-    <div hx-get="/build/step2" hx-trigger="load" hx-target="#wizard" hx-swap="innerHTML"></div>
-    <div hx-get="/build/banner?step=Build%20a%20Deck&i=2&n=5" hx-trigger="load"></div>
-  {% elif step == 3 %}
-    <div hx-get="/build/step3" hx-trigger="load" hx-target="#wizard" hx-swap="innerHTML"></div>
-    <div hx-get="/build/banner?step=Build%20a%20Deck&i=3&n=5" hx-trigger="load"></div>
-  {% elif step == 4 %}
-    <div hx-get="/build/step4" hx-trigger="load" hx-target="#wizard" hx-swap="innerHTML"></div>
-    <div hx-get="/build/banner?step=Build%20a%20Deck&i=4&n=5" hx-trigger="load"></div>
-  {% else %}
-    <div hx-get="/build/step5" hx-trigger="load" hx-target="#wizard" hx-swap="innerHTML"></div>
-    <div hx-get="/build/banner?step=Build%20a%20Deck&i=5&n=5" hx-trigger="load"></div>
-  {% endif %}
-  <noscript><p>Enable JavaScript to use the wizard.</p></noscript>
+  <!-- Wizard content will load here after the modal submit starts the build. -->
+  <noscript><p>Enable JavaScript to build a deck.</p></noscript>
 </div>
 {% endblock %}

code/web/templates/configs/run_result.html

@@ -39,7 +39,7 @@
       
 
       {% if summary %}
-        {% include "partials/deck_summary.html" %}
+        {{ render_cached('partials/deck_summary.html', cfg_name, request=request, summary=summary, game_changers=game_changers, owned_set=owned_set) | safe }}
       {% endif %}
     {% endif %}
 

code/web/templates/decks/compare.html

@@ -0,0 +1,226 @@
+{% extends "base.html" %}
+{% block banner_subtitle %}Compare Decks{% endblock %}
+{% block content %}
+<h2>Compare Decks</h2>
+<p class="muted">Pick two finished decks to compare. You can get here from Finished Decks or deck view pages.</p>
+
+<form method="get" action="/decks/compare" class="panel" style="display:flex; gap:.5rem; align-items:center; flex-wrap:wrap;">
+  <label>Deck A
+    <select name="A" required>
+      <option value="">Choose…</option>
+      {% for opt in options %}
+        <option value="{{ opt.name }}" data-mtime="{{ opt.mtime }}" {% if A == opt.name %}selected{% endif %}>{{ opt.label }}</option>
+      {% endfor %}
+    </select>
+  </label>
+  <label>Deck B
+    <select name="B" required>
+      <option value="">Choose…</option>
+      {% for opt in options %}
+        <option value="{{ opt.name }}" data-mtime="{{ opt.mtime }}" {% if B == opt.name %}selected{% endif %}>{{ opt.label }}</option>
+      {% endfor %}
+    </select>
+  </label>
+  <button type="submit">Compare</button>
+  <button type="button" id="cmp-swap" class="btn" title="Swap A and B" style="margin-left:.25rem;">Swap A/B</button>
+  <button type="button" id="cmp-latest" class="btn" title="Pick the latest two decks">Latest two</button>
+</form>
+
+{% if diffs %}
+  <div class="panel" style="margin-top:.75rem;">
+    <div style="display:flex; gap:1rem; flex-wrap:wrap; align-items:center;">
+      <div>
+        <strong>A:</strong> {{ metaA.display or metaA.filename }}
+        {% if metaA.commander %}<span class="muted">({{ metaA.commander }})</span>{% endif %}
+        {% if metaA.tags %}<div class="muted">{{ metaA.tags }}</div>{% endif %}
+      </div>
+      <div>
+        <strong>B:</strong> {{ metaB.display or metaB.filename }}
+        {% if metaB.commander %}<span class="muted">({{ metaB.commander }})</span>{% endif %}
+        {% if metaB.tags %}<div class="muted">{{ metaB.tags }}</div>{% endif %}
+      </div>
+  <div style="margin-left:auto; display:flex; gap:.5rem; align-items:center;">
+    <button type="button" id="cmp-copy" class="btn" title="Copy a plain-text summary of the diffs">Copy summary</button>
+    <button type="button" id="cmp-download" class="btn" title="Download a plain-text summary of the diffs">Download .txt</button>
+  </div>
+    </div>
+  </div>
+
+  <div class="panel" style="margin-top:.5rem; display:flex; gap:1rem; align-items:center; flex-wrap:wrap;">
+    <div class="muted">Totals:
+      <strong id="totA">{{ (diffs.onlyA|length) if diffs.onlyA else 0 }}</strong> only-in-A,
+      <strong id="totB">{{ (diffs.onlyB|length) if diffs.onlyB else 0 }}</strong> only-in-B,
+      <strong id="totC">{{ (diffs.changed|length) if diffs.changed else 0 }}</strong> changed
+    </div>
+    <label class="muted" style="margin-left:auto; display:flex; align-items:center; gap:.35rem;">
+  <input type="checkbox" id="cmp-changed-only" /> Changed only
+    </label>
+  </div>
+
+  <div class="only-panels" style="display:grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top:.75rem;">
+    <div class="panel onlyA">
+      <h3 style="margin-top:0;">Only in A</h3>
+      {% if diffs.onlyA and diffs.onlyA|length %}
+        <ul>
+          {% for n in diffs.onlyA %}<li>{{ n }}</li>{% endfor %}
+        </ul>
+      {% else %}
+        <div class="muted">None</div>
+      {% endif %}
+    </div>
+    <div class="panel onlyB">
+      <h3 style="margin-top:0;">Only in B</h3>
+      {% if diffs.onlyB and diffs.onlyB|length %}
+        <ul>
+          {% for n in diffs.onlyB %}<li>{{ n }}</li>{% endfor %}
+        </ul>
+      {% else %}
+        <div class="muted">None</div>
+      {% endif %}
+    </div>
+  </div>
+
+  <div class="panel" style="margin-top:1rem;">
+    <h3 style="margin-top:0;">Changed counts</h3>
+    {% if diffs.changed and diffs.changed|length %}
+      <ul class="changed-list">
+        {% for n, a, b in diffs.changed %}
+          {% set delta = b - a %}
+          {% if delta > 0 %}
+            <li class="chg inc" title="Increased in B">▲ {{ n }}: A={{ a }}, B={{ b }} (+{{ delta }})</li>
+          {% elif delta < 0 %}
+            <li class="chg dec" title="Decreased in B">▼ {{ n }}: A={{ a }}, B={{ b }} ({{ delta }})</li>
+          {% else %}
+            <li class="chg">{{ n }}: A={{ a }}, B={{ b }}</li>
+          {% endif %}
+        {% endfor %}
+      </ul>
+    {% else %}
+      <div class="muted">None</div>
+    {% endif %}
+  </div>
+  <script id="cmp-data" type="application/json">{{ {
+      'aLabel': (metaA.display or metaA.filename),
+      'bLabel': (metaB.display or metaB.filename),
+      'onlyA': diffs.onlyA or [],
+      'onlyB': diffs.onlyB or [],
+      'changed': diffs.changed or []
+    } | tojson }}</script>
+  <script>
+  (function(){
+    var copyBtn = document.getElementById('cmp-copy');
+    var dlBtn = document.getElementById('cmp-download');
+    var changedOnly = document.getElementById('cmp-changed-only');
+    var dataEl = document.getElementById('cmp-data');
+    var data = null;
+    try { data = JSON.parse((dataEl && dataEl.textContent) ? dataEl.textContent : 'null'); } catch(e) { data = null; }
+    function buildLines(){
+      var lines = [];
+      lines.push('Compare:');
+      lines.push('A: ' + data.aLabel);
+      lines.push('B: ' + data.bLabel);
+      lines.push('');
+      if (!changedOnly || !changedOnly.checked) {
+        lines.push('Only in A:');
+        if (data.onlyA && data.onlyA.length) { data.onlyA.forEach(function(n){ lines.push('- ' + n); }); }
+        else { lines.push('(none)'); }
+        lines.push('');
+        lines.push('Only in B:');
+        if (data.onlyB && data.onlyB.length) { data.onlyB.forEach(function(n){ lines.push('- ' + n); }); }
+        else { lines.push('(none)'); }
+        lines.push('');
+      }
+      lines.push('Changed counts:');
+      if (data.changed && data.changed.length) {
+        data.changed.forEach(function(row){ lines.push('- ' + row[0] + ': A=' + row[1] + ', B=' + row[2]); });
+      } else { lines.push('(none)'); }
+      return lines;
+    }
+    if (copyBtn) copyBtn.addEventListener('click', function(){
+      try{
+        var txt = buildLines().join('\n');
+        if (navigator.clipboard && navigator.clipboard.writeText){ navigator.clipboard.writeText(txt); }
+        else {
+          var ta = document.createElement('textarea'); ta.value = txt; document.body.appendChild(ta); ta.select(); try{ document.execCommand('copy'); }catch(_){} document.body.removeChild(ta);
+        }
+        if (window.toast) window.toast('Copied comparison');
+      }catch(_){ }
+    });
+    if (dlBtn) dlBtn.addEventListener('click', function(){
+      try{
+        var txt = buildLines().join('\n');
+        var blob = new Blob([txt], {type:'text/plain'});
+        var url = URL.createObjectURL(blob);
+        var a = document.createElement('a');
+        a.href = url;
+        a.download = 'compare.txt';
+        document.body.appendChild(a);
+        a.click();
+        setTimeout(function(){ try{ URL.revokeObjectURL(url); document.body.removeChild(a); }catch(_){ } }, 0);
+      }catch(_){ }
+    });
+    function applyChangedOnlyFlag(){
+      try{
+        var wrap = document.querySelector('.only-panels');
+        if (!wrap || !changedOnly) return;
+        wrap.style.display = changedOnly.checked ? 'none' : 'grid';
+      }catch(_){ }
+    }
+    if (changedOnly) {
+      try {
+        var saved = localStorage.getItem('compare:changedOnly');
+        if (saved === '1') { changedOnly.checked = true; }
+      } catch(_){ }
+      applyChangedOnlyFlag();
+      changedOnly.addEventListener('change', function(){
+        try { localStorage.setItem('compare:changedOnly', this.checked ? '1' : '0'); } catch(_){ }
+        applyChangedOnlyFlag();
+      });
+    }
+    // Swap A/B
+    var swapBtn = document.getElementById('cmp-swap');
+    if (swapBtn) swapBtn.addEventListener('click', function(){
+      try{
+        var f = this.closest('form'); if(!f) return;
+        var a = f.querySelector('select[name="A"]');
+        var b = f.querySelector('select[name="B"]');
+        if(!a || !b) return;
+        var aVal = a.value, bVal = b.value;
+        a.value = bVal; b.value = aVal;
+        f.requestSubmit();
+      }catch(_){ }
+    });
+    // Pick latest two by mtime from options metadata
+    var latestBtn = document.getElementById('cmp-latest');
+    if (latestBtn) latestBtn.addEventListener('click', function(){
+      try{
+        var f = this.closest('form'); if(!f) return;
+        var a = f.querySelector('select[name="A"]');
+        var b = f.querySelector('select[name="B"]');
+        if(!a || !b) return;
+        var opts = Array.from(a.querySelectorAll('option[value]')).filter(function(o){ return o.value; });
+        opts.sort(function(x,y){
+          var mx = parseInt(x.getAttribute('data-mtime') || '0', 10);
+          var my = parseInt(y.getAttribute('data-mtime') || '0', 10);
+          return (my - mx);
+        });
+        if (opts.length >= 2){
+          var first = opts[0].value;
+          var second = opts[1].value;
+          a.value = first; b.value = second;
+          f.requestSubmit();
+        }
+      }catch(_){ }
+    });
+  })();
+  </script>
+<style>
+  .changed-list { list-style: none; padding-left: 0; }
+  .changed-list .chg { padding: 2px 0; }
+  .changed-list .chg.inc { color: #10b981; }
+  .changed-list .chg.dec { color: #ef4444; }
+  .only-panels .onlyA h3 { color: #60a5fa; }
+  .only-panels .onlyB h3 { color: #f59e0b; }
+</style>
+{% endif %}
+{% endblock %}

code/web/templates/decks/index.html

@@ -24,6 +24,10 @@
   </label>
   <button id="deck-clear" type="button" title="Clear filters">Clear</button>
   <button id="deck-share" type="button" title="Copy a shareable link">Share</button>
+  <a href="/decks/compare" class="btn" role="button" title="Compare two finished decks">Compare</a>
+  <button id="deck-compare-selected" type="button" title="Compare two selected decks" disabled>Compare selected</button>
+  <button id="deck-compare-latest" type="button" title="Pick the latest two decks">Latest two</button>
+  <button id="deck-open-permalink" type="button" title="Open a saved permalink">Open Permalink…</button>
   <button id="deck-reset-all" type="button" title="Reset filter, sort, and theme">Reset all</button>
   <button id="deck-help" type="button" title="Keyboard shortcuts and tips" aria-haspopup="dialog" aria-controls="deck-help-modal">Help</button>
   <span id="deck-count" class="muted" aria-live="polite"></span>
@@ -38,7 +42,12 @@
         <div style="display:flex; justify-content:space-between; align-items:center; gap:.5rem;">
           <div>
             <div>
+              {% if it.display %}
+                <strong>{{ it.display }}</strong>
+                <div class="muted" style="font-size:12px;">Commander: <span data-card-name="{{ it.commander }}">{{ it.commander }}</span></div>
+              {% else %}
                 <strong data-card-name="{{ it.commander }}">{{ it.commander }}</strong>
+              {% endif %}
             </div>
             {% if it.tags and it.tags|length %}
             <div class="muted" style="font-size:12px;">Themes: {{ it.tags|join(', ') }}</div>
@@ -50,6 +59,10 @@
             </div>
           </div>
           <div style="display:flex; gap:.35rem; align-items:center;">
+            <label title="Select deck for comparison" style="display:flex; align-items:center; gap:.25rem;">
+              <input type="checkbox" class="deck-select" aria-label="Select deck {{ it.name }} for comparison" />
+              <span class="muted" style="font-size:12px;">Select</span>
+            </label>
             <form action="/files" method="get" style="display:inline; margin:0;">
               <input type="hidden" name="path" value="{{ it.path }}" />
               <button type="submit" title="Download CSV" aria-label="Download CSV for {{ it.commander }}">CSV</button>
@@ -112,11 +125,22 @@
   var helpClose = document.getElementById('deck-help-close');
   var helpBackdrop = document.getElementById('deck-help-backdrop');
   var txtOnlyCb = document.getElementById('deck-txt-only');
+  var cmpSelBtn = document.getElementById('deck-compare-selected');
+  var cmpLatestBtn = document.getElementById('deck-compare-latest');
+  var openPermalinkBtn = document.getElementById('deck-open-permalink');
     if (!list) return;
 
     // Panels and themes discovery from data-tags-pipe
   var panels = Array.prototype.slice.call(list.querySelectorAll('.panel'));
   function refreshPanels(){ panels = Array.prototype.slice.call(list.querySelectorAll('.panel')); }
+  // Selection state for compare
+  var selected = new Set();
+  function updateCompareButtons(){
+    if (!cmpSelBtn) return;
+    var size = selected.size;
+    cmpSelBtn.disabled = (size !== 2);
+    if (cmpSelBtn) cmpSelBtn.title = (size === 2 ? 'Compare the two selected decks' : 'Select exactly two decks to enable');
+  }
   var themeSet = new Set();
   panels.forEach(function(p){
     var raw = p.dataset.tagsPipe || '';
@@ -309,6 +333,31 @@
       updateHashFromState();
     }
 
+  // Wire up compare selection checkboxes
+  function attachSelectHandlers(){
+    try {
+      var cbs = Array.prototype.slice.call(list.querySelectorAll('input.deck-select'));
+      cbs.forEach(function(cb){
+        // Initialize checked state based on current selection
+        var row = cb.closest('.panel');
+        var name = row ? (row.dataset.name || '') : '';
+        cb.checked = selected.has(name);
+        // Apply visual state on init
+        if (row) row.classList.toggle('selected', cb.checked);
+        cb.addEventListener('change', function(){
+          if (!name) return;
+          if (cb.checked) { selected.add(name); }
+          else { selected.delete(name); }
+          // Toggle selection highlight
+          if (row) row.classList.toggle('selected', cb.checked);
+          updateCompareButtons();
+        });
+      });
+      updateCompareButtons();
+    } catch(_){}
+  }
+  attachSelectHandlers();
+
   // Debounce helper
   function debounce(fn, delay){
     var timer = null;
@@ -332,6 +381,53 @@
       applyAll();
     });
 
+  // Compare selected action
+  if (cmpSelBtn) cmpSelBtn.addEventListener('click', function(){
+    try {
+      if (selected.size !== 2) return;
+      var arr = Array.from(selected);
+      var url = '/decks/compare?A=' + encodeURIComponent(arr[0]) + '&B=' + encodeURIComponent(arr[1]);
+      window.location.href = url;
+    } catch(_){ }
+  });
+
+  // Latest two (by modified time across all decks, not just visible)
+  if (cmpLatestBtn) cmpLatestBtn.addEventListener('click', function(){
+    try {
+      // Gather all panels (including hidden) and sort by data-mtime desc
+      var rows = Array.prototype.slice.call(list.querySelectorAll('.panel'));
+      rows.sort(function(a,b){
+        var am = parseFloat(a.dataset.mtime || '0');
+        var bm = parseFloat(b.dataset.mtime || '0');
+        return bm - am;
+      });
+      // Take first two distinct names
+      var pick = [];
+      for (var i=0; i<rows.length && pick.length<2; i++){
+        var nm = rows[i].dataset.name || '';
+        if (nm && pick.indexOf(nm) === -1) pick.push(nm);
+      }
+      if (pick.length === 2){
+        var url = '/decks/compare?A=' + encodeURIComponent(pick[0]) + '&B=' + encodeURIComponent(pick[1]);
+        window.location.href = url;
+      } else {
+        if (window.toast) window.toast('Need at least two decks');
+      }
+    } catch(_){ }
+  });
+
+  // Open permalink prompt
+  if (openPermalinkBtn) openPermalinkBtn.addEventListener('click', function(){
+    try{
+      var token = prompt('Paste a /build/from?state=... URL or token:');
+      if(!token) return;
+      var m = token.match(/state=([^&]+)/);
+      var t = m ? m[1] : token.trim();
+      if(!t) return;
+      window.location.href = '/build/from?state=' + encodeURIComponent(t);
+    }catch(_){ }
+  });
+
   if (resetAllBtn) resetAllBtn.addEventListener('click', function(){
       // Clear UI state
       try {
@@ -408,6 +504,10 @@
     // React to external hash changes
     window.addEventListener('hashchange', function(){ applyStateFromHash(); });
 
+  // Re-attach selection handlers when list changes order
+  var observer = new MutationObserver(function(){ attachSelectHandlers(); });
+  try { observer.observe(list, { childList: true }); } catch(_){ }
+
     // Open deck: keyboard and mouse helpers on panels
     function getPanelUrl(p){
       try {
@@ -551,5 +651,6 @@
   mark { background: rgba(251, 191, 36, .35); color: inherit; padding:0 .1rem; border-radius:2px; }
   #deck-list[role="list"] .panel[role="listitem"] { outline: none; }
   #deck-list[role="list"] .panel[role="listitem"]:focus { box-shadow: 0 0 0 2px #3b82f6 inset; }
+    #deck-list .panel.selected { box-shadow: 0 0 0 2px #10b981 inset; border-color: #10b981; }
 </style>
 {% endblock %}

code/web/templates/decks/view.html

@@ -2,6 +2,9 @@
 {% block banner_subtitle %}Finished Decks{% endblock %}
 {% block content %}
 <h2>Finished Deck</h2>
+{% if display_name %}
+  <div><strong>{{ display_name }}</strong></div>
+{% endif %}
 <div class="muted">Commander: <strong data-card-name="{{ commander }}">{{ commander }}</strong>{% if tags and tags|length %} • Themes: {{ tags|join(', ') }}{% endif %}</div>
 <div class="muted">This view mirrors the end-of-build summary. Use the buttons to download the CSV/TXT exports.</div>
 
@@ -24,6 +27,7 @@
         <button type="submit">Download TXT</button>
       </form>
       {% endif %}
+  <a href="/decks/compare?A={{ name|urlencode }}" class="btn" role="button" title="Compare this deck with another">Compare…</a>
       <form method="get" action="/decks" style="display:inline; margin:0;">
         <button type="submit">Back to Finished Decks</button>
       </form>
@@ -54,7 +58,7 @@
           </div>
         </div>
       {% endif %}
-      {% include "partials/deck_summary.html" %}
+  {{ render_cached('partials/deck_summary.html', name, request=request, summary=summary, game_changers=game_changers, owned_set=owned_set) | safe }}
     {% else %}
       <div class="muted">No summary available.</div>
     {% endif %}

code/web/templates/diagnostics/index.html

@@ -7,6 +7,15 @@
     <h3 style="margin-top:0">System summary</h3>
     <div id="sysSummary" class="muted">Loading…</div>
   </div>
+  <div class="card" style="background:#0f1115; border:1px solid var(--border); border-radius:10px; padding:.75rem; margin-bottom:.75rem">
+    <h3 style="margin-top:0">Performance (local)</h3>
+    <div class="muted" style="margin-bottom:.35rem">Scroll the Step 5 list; this panel shows a rough FPS estimate and virtualization renders.</div>
+    <div style="display:flex; gap:1rem; flex-wrap:wrap">
+      <div><strong>Scroll FPS:</strong> <span id="perf-fps">–</span></div>
+      <div><strong>Visible tiles:</strong> <span id="perf-visible">–</span></div>
+      <div><strong>Render count:</strong> <span id="perf-renders">0</span></div>
+    </div>
+  </div>
   <div class="card" style="background:#0f1115; border:1px solid var(--border); border-radius:10px; padding:.75rem;">
   <h3 style="margin-top:0">Error triggers</h3>
     <div class="row" style="display:flex; gap:.5rem; align-items:center">
@@ -39,6 +48,40 @@
     try { fetch('/status/sys', { cache: 'no-store' }).then(function(r){ return r.json(); }).then(render).catch(function(){ el.textContent='Unavailable'; }); } catch(_){ el.textContent='Unavailable'; }
   }
   load();
+  // Perf probe: listen to scroll on a card grid if present
+  try{
+    var fpsEl = document.getElementById('perf-fps');
+    var visEl = document.getElementById('perf-visible');
+    var rcEl = document.getElementById('perf-renders');
+    var grid = document.querySelector('.card-grid');
+    var last = performance.now();
+    var frames = 0; var renders = 0;
+    function tick(){
+      frames++;
+      var now = performance.now();
+      if (now - last >= 500){
+        var fps = Math.round((frames * 1000) / (now - last));
+        if (fpsEl) fpsEl.textContent = String(fps);
+        frames = 0; last = now;
+      }
+      requestAnimationFrame(tick);
+    }
+    requestAnimationFrame(tick);
+    function updateVisible(){
+      try{
+        if (!grid) return;
+        var tiles = grid.querySelectorAll('.card-tile');
+        var c = 0; tiles.forEach(function(t){ if (t.style.display !== 'none') c++; });
+        if (visEl) visEl.textContent = String(c);
+      }catch(_){ }
+    }
+    if (grid){
+      grid.addEventListener('scroll', updateVisible);
+      var mo = new MutationObserver(function(){ renders++; if (rcEl) rcEl.textContent = String(renders); updateVisible(); });
+      mo.observe(grid, { childList: true, subtree: true, attributes: false });
+      updateVisible();
+    }
+  }catch(_){ }
 })();
 </script>
 {% endblock %}

code/web/templates/diagnostics/perf.html

@@ -0,0 +1,71 @@
+{% extends "base.html" %}
+{% block content %}
+<section>
+  <h2>Diagnostics: Synthetic Perf Probe</h2>
+  <p class="muted">Scroll the list; we estimate FPS and count re-renders. This page is only available when diagnostics are enabled.</p>
+  <div style="display:flex; gap:1rem; flex-wrap:wrap; margin:.5rem 0 1rem 0;">
+    <div><strong>FPS:</strong> <span id="fps">–</span></div>
+    <div><strong>Visible rows:</strong> <span id="rows">–</span></div>
+    <div><strong>Render count:</strong> <span id="renders">0</span></div>
+  </div>
+
+  <div id="probe" style="height:60vh; overflow:auto; border:1px solid var(--border); border-radius:8px; background:#0f1115;">
+    <ul id="list" style="list-style:none; margin:0; padding:0; display:grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap:8px 12px;">
+      {% for i in range(1,1201) %}
+      <li style="padding:.5rem; border:1px solid var(--border); border-radius:8px; background:#0b0d12;">
+        <div style="display:flex; align-items:center; gap:.5rem;">
+          <div style="width:64px; height:40px; background:#111; border:1px solid var(--border); border-radius:6px;">
+            <img class="card-thumb" alt="Thumb {{ i }}" loading="lazy" decoding="async" data-lqip
+                 src="https://api.scryfall.com/cards/named?fuzzy=Lightning%20Bolt&format=image&version=small"
+                 width="64" height="40" style="width:64px; height:40px; object-fit:cover; border-radius:6px;" />
+          </div>
+          <div style="display:flex; flex-direction:column; gap:.25rem;">
+            <strong>Row {{ i }}</strong>
+            <small class="muted">Synthetic item for performance testing</small>
+          </div>
+        </div>
+      </li>
+      {% endfor %}
+    </ul>
+  </div>
+</section>
+<script>
+(function(){
+  var probe = document.getElementById('probe');
+  var list = document.getElementById('list');
+  var fpsEl = document.getElementById('fps');
+  var rowsEl = document.getElementById('rows');
+  var rcEl = document.getElementById('renders');
+  var last = performance.now();
+  var frames = 0; var renders = 0;
+  function raf(){
+    frames++;
+    var now = performance.now();
+    if (now - last >= 500){
+      var fps = Math.round((frames * 1000) / (now - last));
+      if (fpsEl) fpsEl.textContent = String(fps);
+      frames = 0; last = now;
+    }
+    requestAnimationFrame(raf);
+  }
+  requestAnimationFrame(raf);
+  function updateVisible(){
+    if (!probe || !list) return;
+    var count = 0;
+    list.querySelectorAll('li').forEach(function(li){
+      // rough: count if within viewport
+      var rect = li.getBoundingClientRect();
+      var pRect = probe.getBoundingClientRect();
+      if (rect.bottom >= pRect.top && rect.top <= pRect.bottom) count++;
+    });
+    if (rowsEl) rowsEl.textContent = String(count);
+  }
+  if (probe){
+    probe.addEventListener('scroll', updateVisible);
+    var mo = new MutationObserver(function(){ renders++; if (rcEl) rcEl.textContent = String(renders); updateVisible(); });
+    mo.observe(list, { childList: true, subtree: true });
+    updateVisible();
+  }
+})();
+</script>
+{% endblock %}

code/web/templates/owned/index.html

@@ -70,7 +70,7 @@
   {% endif %}
 
   {% if names and names|length %}
-  <div id="owned-box" style="overflow:auto; border:1px solid var(--border); border-radius:8px; padding:.5rem; background:#0f1115; color:#e5e7eb; min-height:240px;">
+  <div id="owned-box" style="overflow:auto; border:1px solid var(--border); border-radius:8px; padding:.5rem; background:#0f1115; color:#e5e7eb; min-height:240px;" {% if virtualize %}data-virtualize="1"{% endif %}>
     <ul id="owned-grid" style="display:grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); grid-auto-rows:auto; gap:4px 16px; list-style:none; margin:0; padding:0;">
       {% for n in names %}
       {% set tags = (tags_by_name.get(n, []) if tags_by_name else []) %}
@@ -81,7 +81,9 @@
   <label class="owned-row" style="cursor:pointer;" tabindex="0">
           <input type="checkbox" class="sel sr-only" aria-label="Select {{ n }}" />
           <div class="owned-vstack">
-            <img class="card-thumb" loading="lazy" alt="{{ n }} image" src="https://api.scryfall.com/cards/named?fuzzy={{ n|urlencode }}&format=image&version=small" data-card-name="{{ n }}" {% if tags %}data-tags="{{ (tags or [])|join(', ') }}"{% endif %} />
+  <img class="card-thumb" loading="lazy" decoding="async" alt="{{ n }} image" src="https://api.scryfall.com/cards/named?fuzzy={{ n|urlencode }}&format=image&version=small" data-card-name="{{ n }}" data-lqip="1" {% if tags %}data-tags="{{ (tags or [])|join(', ') }}"{% endif %}
+        srcset="https://api.scryfall.com/cards/named?fuzzy={{ n|urlencode }}&format=image&version=small 160w, https://api.scryfall.com/cards/named?fuzzy={{ n|urlencode }}&format=image&version=normal 488w"
+        sizes="100px" />
             <span class="card-name"{% if tags %} data-tags="{{ (tags or [])|join(', ') }}"{% endif %}>{{ n }}</span>
             {% if cols and cols|length %}
             <div class="mana-group" aria-hidden="true">

code/web/templates/partials/deck_summary.html

@@ -81,7 +81,9 @@
               {% set cnt = c.count if c.count else 1 %}
               {% set owned = (owned_set is defined and c.name and (c.name|lower in owned_set)) %}
               <div class="stack-card {% if (game_changers and (c.name in game_changers)) or ('game_changer' in (c.role or '') or 'Game Changer' in (c.role or '')) %}game-changer{% endif %}">
-                <img src="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal" alt="{{ c.name }} image" data-card-name="{{ c.name }}" data-count="{{ cnt }}" data-role="{{ c.role }}" data-tags="{{ (c.tags|join(', ')) if c.tags else '' }}" />
+                <img class="card-thumb" loading="lazy" decoding="async" src="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal" alt="{{ c.name }} image" data-card-name="{{ c.name }}" data-count="{{ cnt }}" data-role="{{ c.role }}" data-tags="{{ (c.tags|join(', ')) if c.tags else '' }}"
+                     srcset="https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=small 160w, https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=normal 488w, https://api.scryfall.com/cards/named?fuzzy={{ c.name|urlencode }}&format=image&version=large 672w"
+                     sizes="(max-width: 1200px) 160px, 240px" />
                 <div class="count-badge">{{ cnt }}x</div>
                 <div class="owned-badge" title="{{ 'Owned' if owned else 'Not owned' }}" aria-label="{{ 'Owned' if owned else 'Not owned' }}">{% if owned %}✔{% else %}✖{% endif %}</div>
               </div>
@@ -561,6 +563,12 @@
           if (!on && !match) tile.classList.remove('chart-highlight');
         });
       } catch(_) {}
+      // If virtualized lists are enabled, auto-scroll the Step 5 grid to the first match
+      try {
+        if (on && window.scrollCardIntoView && Array.isArray(names) && names.length) {
+          window.scrollCardIntoView(names[0]);
+        }
+      } catch(_) {}
     }
     attach();
     document.addEventListener('htmx:afterSwap', function() { attach(); });

docker-compose.yml

@@ -38,6 +38,8 @@ services:
       # Speed up setup/tagging in Web UI via parallel workers
       - WEB_TAG_PARALLEL=1
       - WEB_TAG_WORKERS=4
+      # Enable virtualization + lazy image tweaks in Step 5
+      - WEB_VIRTUALIZE=1
     volumes:
       - ${PWD}/deck_files:/app/deck_files
       - ${PWD}/logs:/app/logs

run-web-from-dockerhub.bat

@@ -14,13 +14,14 @@ if not exist "owned_cards" mkdir owned_cards
 REM Flags (override by setting env vars before running)
 if "%SHOW_LOGS%"=="" set SHOW_LOGS=1
 if "%SHOW_DIAGNOSTICS%"=="" set SHOW_DIAGNOSTICS=1
+if "%WEB_VIRTUALIZE%"=="" set WEB_VIRTUALIZE=0
 
 echo Starting Web UI on http://localhost:8080
-printf Flags: SHOW_LOGS=%SHOW_LOGS%  SHOW_DIAGNOSTICS=%SHOW_DIAGNOSTICS%
+printf Flags: SHOW_LOGS=%SHOW_LOGS%  SHOW_DIAGNOSTICS=%SHOW_DIAGNOSTICS%  WEB_VIRTUALIZE=%WEB_VIRTUALIZE%
 
 docker run --rm ^
   -p 8080:8080 ^
-  -e SHOW_LOGS=%SHOW_LOGS% -e SHOW_DIAGNOSTICS=%SHOW_DIAGNOSTICS% ^
+  -e SHOW_LOGS=%SHOW_LOGS% -e SHOW_DIAGNOSTICS=%SHOW_DIAGNOSTICS% -e WEB_VIRTUALIZE=%WEB_VIRTUALIZE% ^
   -v "%cd%\deck_files:/app/deck_files" ^
   -v "%cd%\logs:/app/logs" ^
   -v "%cd%\csv_files:/app/csv_files" ^