fix(#1356): replace HTTPServer with ThreadingHTTPServer in multi-user bridge

The single-threaded HTTPServer queues requests sequentially, causing
60% timeout under 10 concurrent users (30s timeout, 7.8s avg).

Fix: use ThreadingHTTPServer (already defined in multi_user_bridge.py)
for thread-per-request concurrency.

- multi_user_bridge.py: line 2883 HTTPServer -> ThreadingHTTPServer
- world/multi_user_bridge.py: add ThreadingMixIn import + class, fix server init

Refs #1356

multi_user_bridge.py

@@ -2880,7 +2880,7 @@ def main():
     # Start world tick system
     world_tick_system.start()
 
-    server = HTTPServer((BRIDGE_HOST, BRIDGE_PORT), BridgeHandler)
+    server = ThreadingHTTPServer((BRIDGE_HOST, BRIDGE_PORT), BridgeHandler)
     server.serve_forever()
 
 

world/multi_user_bridge.py

@@ -26,11 +26,17 @@ import threading
 import hashlib
 import os
 import sys
-from http.server import HTTPServer, BaseHTTPRequestHandler
+from http.server import BaseHTTPRequestHandler, HTTPServer
+from socketserver import ThreadingMixIn
 from pathlib import Path
 from datetime import datetime
 from typing import Optional
 
+
+class ThreadingHTTPServer(ThreadingMixIn, HTTPServer):
+    """Thread-per-request HTTP server."""
+    daemon_threads = True
+
 # ── Configuration ──────────────────────────────────────────────────────
 
 BRIDGE_PORT = int(os.environ.get('TIMMY_BRIDGE_PORT', 4004))
@@ -274,7 +280,7 @@ def main():
     print(f"  POST /bridge/move      — Move user to room (user_id, room)")
     print()
     
-    server = HTTPServer((BRIDGE_HOST, BRIDGE_PORT), BridgeHandler)
+    server = ThreadingHTTPServer((BRIDGE_HOST, BRIDGE_PORT), BridgeHandler)
     server.serve_forever()