feat(web): Core Refactor Phase A — extract sampling and cache modules; add adaptive TTL + eviction heuristics, Redis PoC, and metrics wiring. Tests added for TTL, eviction, exports, splash-adaptive, card index, and service worker. Docs+roadmap updated.

code/scripts/snapshot_taxonomy.py

@@ -0,0 +1,94 @@
+"""Snapshot the current power bracket taxonomy to a dated JSON artifact.
+
+Outputs a JSON file under logs/taxonomy_snapshots/ named
+  taxonomy_<YYYYMMDD>_<HHMMSS>.json
+containing:
+  {
+    "generated_at": ISO8601,
+    "hash": sha256 hex of canonical payload (excluding this top-level wrapper),
+    "brackets": [ {level,name,short_desc,long_desc,limits} ... ]
+  }
+
+If a snapshot with identical hash already exists today, creation is skipped
+unless --force provided.
+
+Usage (from repo root):
+  python -m code.scripts.snapshot_taxonomy
+  python -m code.scripts.snapshot_taxonomy --force
+
+Intended to provide an auditable evolution trail for taxonomy adjustments
+before we implement taxonomy-aware sampling changes.
+"""
+from __future__ import annotations
+
+import argparse
+import json
+import hashlib
+from datetime import datetime
+from pathlib import Path
+from typing import Any, Dict
+
+from code.deck_builder.phases.phase0_core import BRACKET_DEFINITIONS
+
+SNAP_DIR = Path("logs/taxonomy_snapshots")
+SNAP_DIR.mkdir(parents=True, exist_ok=True)
+
+
+def _canonical_brackets():
+    return [
+        {
+            "level": b.level,
+            "name": b.name,
+            "short_desc": b.short_desc,
+            "long_desc": b.long_desc,
+            "limits": b.limits,
+        }
+        for b in sorted(BRACKET_DEFINITIONS, key=lambda x: x.level)
+    ]
+
+
+def compute_hash(brackets) -> str:
+    # Canonical JSON with sorted keys for repeatable hash
+    payload = json.dumps(brackets, sort_keys=True, separators=(",", ":"))
+    return hashlib.sha256(payload.encode("utf-8")).hexdigest()
+
+
+def find_existing_hashes() -> Dict[str, Path]:
+    existing = {}
+    for p in SNAP_DIR.glob("taxonomy_*.json"):
+        try:
+            data = json.loads(p.read_text(encoding="utf-8"))
+            h = data.get("hash")
+            if h:
+                existing[h] = p
+        except Exception:
+            continue
+    return existing
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--force", action="store_true", help="Write new snapshot even if identical hash exists today")
+    args = ap.parse_args()
+
+    brackets = _canonical_brackets()
+    h = compute_hash(brackets)
+    existing = find_existing_hashes()
+    if h in existing and not args.force:
+        print(f"Snapshot identical (hash={h[:12]}...) exists: {existing[h].name}; skipping.")
+        return 0
+
+    ts = datetime.utcnow().strftime("%Y%m%d_%H%M%S")
+    out = SNAP_DIR / f"taxonomy_{ts}.json"
+    wrapper: Dict[str, Any] = {
+        "generated_at": datetime.utcnow().isoformat() + "Z",
+        "hash": h,
+        "brackets": brackets,
+    }
+    out.write_text(json.dumps(wrapper, indent=2, sort_keys=True) + "\n", encoding="utf-8")
+    print(f"Wrote taxonomy snapshot {out} (hash={h[:12]}...)")
+    return 0
+
+
+if __name__ == "__main__":  # pragma: no cover
+    raise SystemExit(main())