Add uvicorn workers and Redis timeouts

- Run uvicorn with 4 workers to handle concurrent requests
- Add socket_timeout and socket_connect_timeout to Redis client (5s)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

server.py

@@ -66,7 +66,9 @@ parsed = urlparse(REDIS_URL)
 redis_client = redis.Redis(
     host=parsed.hostname or 'localhost',
     port=parsed.port or 6379,
-    db=int(parsed.path.lstrip('/') or 0)
+    db=int(parsed.path.lstrip('/') or 0),
+    socket_timeout=5,
+    socket_connect_timeout=5
 )
 RUNS_KEY_PREFIX = "artdag:run:"
 RECIPES_KEY_PREFIX = "artdag:recipe:"
@@ -3986,4 +3988,4 @@ async def ui_run_partial(run_id: str, request: Request):
 
 if __name__ == "__main__":
     import uvicorn
-    uvicorn.run(app, host="0.0.0.0", port=8100)
+    uvicorn.run(app, host="0.0.0.0", port=8100, workers=4)