PUBG drop map: live squad map with WebSocket rooms

- server.js wraps Bun.serve to add /ws/<channel> upgrades (same server and port) and
  serve the map tiles from the host mount; Dockerfile now runs bun ./server.js
- ws hub (channel registry, origin check) + pubg-map channel: rooms by unguessable
  code, validated + rate-limited messages, per-room write queue, presence
- games.pubg_rooms / pubg_matches / pubg_markers; per-match sessions with history
- /trackers/games/pubg/map hub (owner: rooms, landings over time, history) and
  /trackers/games/pubg/map/<code> fullscreen Leaflet map (all 11 maps)
- deploy-remote.sh bind-mounts ~/pubg-maps; scripts/build-pubg-tiles.py rebuilds it

Dockerfile

@@ -24,8 +24,11 @@ COPY --from=builder /app/src/lib/availability.ts ./src/lib/availability.ts
 COPY --from=builder /app/src/lib/music ./src/lib/music
 # scripts/games-ingest.ts (match history backfills) imports the games ingest.
 COPY --from=builder /app/src/lib/games-ingest ./src/lib/games-ingest
+COPY --from=builder /app/server.js ./server.js
 COPY package.json ./
 EXPOSE 3000
 ENV NODE_ENV=production
 ENV BODY_SIZE_LIMIT=6M
-CMD ["bun", "./build"]
+# server.js wraps the adapter-bun build: same server, plus /ws/<channel> WebSockets and the
+# PUBG map tiles (/pubg-tiles from the PUBG_TILES_ROOT bind mount, see scripts/deploy-remote.sh).
+CMD ["bun", "./server.js"]