Web UI polish: thumbnail-hover preview, white thumbnail selection, Themes bullet list; global Scryfall image retry (thumbs+previews) with fallbacks and cache-bust; standardized data-card-name. Deck Summary alignment overhaul (count//name/owned grid, tabular numerals, inset highlight, tooltips, starts under header). Added diagnostics (health + logs pages, error pages, request-id propagation), global HTMX error toasts, and docs updates. Update DOCKER guide and add run-web scripts. Update CHANGELOG and release notes template.

code/tests/test_diagnostics.py

@@ -0,0 +1,82 @@
+import os
+import importlib
+import types
+import pytest
+from starlette.testclient import TestClient
+
+fastapi = pytest.importorskip("fastapi")  # skip tests if FastAPI isn't installed
+
+
+def load_app_with_env(**env: str) -> types.ModuleType:
+    for k, v in env.items():
+        os.environ[k] = v
+    import code.web.app as app_module  # type: ignore
+    importlib.reload(app_module)
+    return app_module
+
+
+def test_healthz_ok_and_request_id_header():
+    app_module = load_app_with_env()
+    client = TestClient(app_module.app)
+    r = client.get("/healthz")
+    assert r.status_code == 200
+    data = r.json()
+    assert data.get("status") in {"ok", "degraded"}
+    assert "uptime_seconds" in data
+    assert r.headers.get("X-Request-ID")
+
+
+def test_404_renders_html_when_accept_html():
+    app_module = load_app_with_env()
+    client = TestClient(app_module.app)
+    r = client.get("/this-does-not-exist", headers={"Accept": "text/html"})
+    assert r.status_code == 404
+    body = r.text.lower()
+    assert "page not found" in body
+    assert "go home" in body
+    assert r.headers.get("X-Request-ID")
+
+
+def test_htmx_http_exception_returns_json_with_request_id():
+    app_module = load_app_with_env(SHOW_DIAGNOSTICS="1")
+    client = TestClient(app_module.app)
+    r = client.get("/diagnostics/trigger-error", headers={"HX-Request": "true"})
+    assert r.status_code == 418
+    data = r.json()
+    assert data.get("error") is True
+    assert data.get("status") == 418
+    assert data.get("request_id")
+    assert r.headers.get("X-Request-ID")
+
+
+def test_unhandled_exception_returns_500_json_with_request_id():
+    app_module = load_app_with_env(SHOW_DIAGNOSTICS="1")
+    # Configure client to not re-raise server exceptions so we can assert the 500 response
+    client = TestClient(app_module.app, raise_server_exceptions=False)
+    r = client.get("/diagnostics/trigger-error?kind=unhandled", headers={"HX-Request": "true"})
+    assert r.status_code == 500
+    data = r.json()
+    assert data.get("error") is True
+    assert data.get("status") == 500
+    assert data.get("request_id")
+    assert r.headers.get("X-Request-ID")
+
+
+def test_status_sys_summary_and_flags():
+    app_module = load_app_with_env(
+        SHOW_LOGS="1",
+        SHOW_DIAGNOSTICS="1",
+        SHOW_SETUP="1",
+        APP_VERSION="testver",
+    )
+    client = TestClient(app_module.app)
+    r = client.get("/status/sys")
+    assert r.status_code == 200
+    data = r.json()
+    assert data.get("version") == "testver"
+    assert isinstance(data.get("uptime_seconds"), int)
+    assert isinstance(data.get("server_time_utc"), str)
+    flags = data.get("flags") or {}
+    assert flags.get("SHOW_LOGS") is True
+    assert flags.get("SHOW_DIAGNOSTICS") is True
+    assert flags.get("SHOW_SETUP") is True