Handle abrupt WebSocket disconnect (e.g. Safari tab close)

Catch ConnectionClosed in User.send() and handler_recv() so that an
unclean client disconnect no longer produces "Task exception was never
retrieved" / "connection handler failed" log noise.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SH2D4LRuCnhLSzoYerAfJX

ws/server/ws_server_multi_user.py

@@ -1,4 +1,5 @@
 import asyncio
+import websockets.exceptions
 from ws.server.ws_server import WsServer
 from ws.user import User, UserSet, update
 from ws.connection import IConnection
@@ -31,14 +32,17 @@ class WsServerMultiUser(WsServer):
 		await self.notify_users()
 
 	async def handler_recv(self, websocket, path):
-		while True:
-			data = await websocket.recv()
-			usr = self.USERS.get(websocket)
-			processed = await usr.process(data)
-			if processed:
-				await usr.send(self.global_state)
-			else:
-				await self.listener.on_recv(data)
+		try:
+			while True:
+				data = await websocket.recv()
+				usr = self.USERS.get(websocket)
+				processed = await usr.process(data)
+				if processed:
+					await usr.send(self.global_state)
+				else:
+					await self.listener.on_recv(data)
+		except websockets.exceptions.ConnectionClosed:
+			pass
 
 	async def handler_send(self, websocket, path):
 		while True: