Add Command Center web UI (no build step)

Static HTML/CSS/JS served by FastAPI (mounted at /ui, / redirects there),
talking to the existing JSON API — no node/npm, no bundler.

- games/versions sidebar with A/B version selectors
- visual 4-axis diff (types/methods/events/fields, +/- struct_layout) with
  +/-/~ rows, per-axis counts, class (owner) filter, moved-methods section
- single-snapshot browser (tabs + live filter)
- app.py mounts StaticFiles(html=True) last so API routes win; / -> /ui/

Smoke-tested live on uvicorn: /, /ui/ and assets serve 200; UI wiring drives
the same /games and /diff endpoints verified end-to-end. app.js passes
`node --check`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -71,6 +71,12 @@ uvicorn ams.api.app:create_app --factory --reload  # serwer
 Endpointy: `POST/GET /games`, `POST/GET /snapshots` (import deduplikowany po sha256),
 `GET /diff?old=&new=[&owner=]`, `GET /health`. Testy: `pytest` (11, w tym integracyjne na golden pair).
 
+## Front — Command Center
+
+Po starcie serwera otwórz **http://127.0.0.1:8000/** (`/` → `/ui/`). Statyczny UI bez build-stepu
+(czysty HTML/CSS/JS w `ams/api/static/`, serwowany przez FastAPI): lista gier/wersji, wybór dwóch
+wersji (A/B), wizualny diff po 4 osiach z filtrem klasy i przeglądarka pojedynczej powierzchni.
+
 ## Format snapshotu
 
 `schema_version`, `binary{name,sha256,engine,compiler,factory_addr}`, oraz listy