fix: 7 bug fixes + port config with auto-restart

- HTTPException import added (was causing 500 on missing dashboard)
- game_manager.remove_plugin() restored (was AttributeError)
- api.js checks HTTP status codes, fails fast on errors
- sidebar game highlight only matches selected gameId
- scene resize handler uses stored canvas dims (was NaN)
- forwarder socket properly closed on listener stop
- telemetry port: use_unified_port toggle, off = per-game port, auto-restart on switch

config/settings.py

@@ -17,6 +17,7 @@ DEFAULT_CONFIG: dict[str, Any] = {
     "theme": "dark",
     "sidebar_collapsed": False,
     "telemetry_port": 20777,
+    "use_unified_port": True,
     "telemetry_host": "0.0.0.0",
     "server_host": "0.0.0.0",
     "server_port": 9527,