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

src/lib/chrome.ts

@@ -4,7 +4,11 @@
  * only imports SiteChrome for other pages.
  */
 export function isImmersive(pathname: string): boolean {
-	return /^\/trackers\/books\/\d+\/read\/?$/.test(pathname);
+	return (
+		/^\/trackers\/books\/\d+\/read\/?$/.test(pathname) ||
+		// A PUBG drop map room (full-screen, for a second monitor).
+		/^\/trackers\/games\/pubg\/map\/[A-Za-z0-9]{20}\/?$/.test(pathname)
+	);
 }
 
 /** Pages that show the site header but no footer: the /start new-tab dashboard. */