fix(#1356): Replace HTTPServer with ThreadingHTTPServer for concurrent users

The multi-user bridge used single-threaded HTTPServer which processed
requests sequentially. Each LLM inference call (5-10s) blocked all
other users, causing 60% timeout rate at 10 concurrent connections.

Changes:
  - world/multi_user_bridge.py: Added ThreadingMixIn import,
    ThreadingHTTPServer class with daemon_threads, swapped
    HTTPServer -> ThreadingHTTPServer in main()
  - multi_user_bridge.py (root): Fixed main() to use the already-
    defined ThreadingHTTPServer class instead of raw HTTPServer

Fixes #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 +26,18 @@ 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 server for concurrent multi-user handling."""
+    daemon_threads = True
+
+
 # ── Configuration ──────────────────────────────────────────────────────
 
 BRIDGE_PORT = int(os.environ.get('TIMMY_BRIDGE_PORT', 4004))
@@ -274,7 +281,7 @@ 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()