feat: add ZMQ timeout configurations to prevent hanging

- Add RCVTIMEO (300s) to prevent recv operations from hanging indefinitely
- Add SNDTIMEO (300s) to prevent send operations from hanging indefinitely
- Add IMMEDIATE mode to avoid message queue blocking
- Applied to both api.py and searcher_base.py ZMQ socket connections

This ensures ZMQ operations timeout gracefully instead of hanging the process
when embedding servers become unresponsive.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

packages/leann-core/src/leann/api.py

@@ -88,6 +88,9 @@ def compute_embeddings_via_server(chunks: list[str], model_name: str, port: int)
     context = zmq.Context()
     socket = context.socket(zmq.REQ)
     socket.setsockopt(zmq.LINGER, 0)  # Don't block on close
+    socket.setsockopt(zmq.RCVTIMEO, 300000)  # 300秒接收超时
+    socket.setsockopt(zmq.SNDTIMEO, 300000)  # 300秒发送超时
+    socket.setsockopt(zmq.IMMEDIATE, 1)  # 立即模式，避免队列阻塞
     socket.connect(f"tcp://localhost:{port}")
 
     try:

packages/leann-core/src/leann/searcher_base.py

@@ -138,6 +138,9 @@ class BaseSearcher(LeannBackendSearcherInterface, ABC):
             context = zmq.Context()
             socket = context.socket(zmq.REQ)
             socket.setsockopt(zmq.LINGER, 0)  # Don't block on close
+            socket.setsockopt(zmq.RCVTIMEO, 300000)  # 300秒接收超时
+            socket.setsockopt(zmq.SNDTIMEO, 300000)  # 300秒发送超时
+            socket.setsockopt(zmq.IMMEDIATE, 1)  # 立即模式，避免队列阻塞
             socket.connect(f"tcp://localhost:{zmq_port}")
 
             # Send embedding request