Initial TopDeck: self-hosted ranked favorites

A single Go binary with SQLite that serves a public page of the owner's
ranked lists (movies, TV, albums, songs, video games, theater) and a
login-gated editor.

- Lists of 1–65,535 entries (100 recommended), several per category
- Search-to-add via TMDB, TheTVDB, IGDB, Deezer/MusicBrainz, Wikipedia;
  manual entry as a fallback
- Theater entries carry a production (Broadway, tour, …), venue and cast
- Artwork cached locally; URL override and uploads
- Drag, arrow and type-a-rank reordering; paginated for long lists
- 12 theme presets plus custom CSS
- First-run setup code or env-provided admin; bcrypt, rate-limited login,
  CSRF-guarded JSON API
- Dockerfile and docker-compose.yml

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docker-compose.yml

@@ -0,0 +1,16 @@
+services:
+  topdeck:
+    build: .
+    image: topdeck:latest
+    container_name: topdeck
+    restart: unless-stopped
+    ports:
+      - "4242:4242"
+    volumes:
+      - topdeck-data:/data
+    env_file:
+      - path: .env
+        required: false
+
+volumes:
+  topdeck-data: