fix(proxy-tunnel): 修复隧道连接池竞态与跨平台兼容问题

- 修复 TCP keepalive with_retries 在 Windows 上不可用的编译问题
- dispatcher 中 try_send 失败时记录警告日志而非静默丢弃
- 优化 handler_handles 清理策略，每 64 帧定期清理
- StreamState 记住原始连接引用，清理时避免连接池竞态

src/services/proxy_node/tunnel_manager.py

@@ -63,7 +63,7 @@ class TunnelConnection:
             raise TunnelStreamError("frame send timeout (writer congested)")
 
     def create_stream(self, stream_id: int) -> _StreamState:
-        state = _StreamState(stream_id)
+        state = _StreamState(stream_id, conn=self)
         self._pending_streams[stream_id] = state
         return state
 
@@ -109,9 +109,10 @@ class _StreamState:
         "_body_chunks",
         "_done_event",
         "_error",
+        "_conn",
     )
 
-    def __init__(self, stream_id: int) -> None:
+    def __init__(self, stream_id: int, conn: TunnelConnection | None = None) -> None:
         self.stream_id = stream_id
         self.status: int = 0
         self.headers: list[list[str]] = []
@@ -119,6 +120,7 @@ class _StreamState:
         self._body_chunks: asyncio.Queue[bytes | None] = asyncio.Queue()
         self._done_event = asyncio.Event()
         self._error: str | None = None
+        self._conn = conn
 
     def set_response_headers(self, status: int, headers: list[list[str]] | dict[str, str]) -> None:
         self.status = status

src/services/proxy_node/tunnel_transport.py

@@ -95,7 +95,10 @@ class TunnelTransport(httpx.AsyncBaseTransport):
     def _cleanup_stream(self, manager: TunnelManager, stream_state: _StreamState | None) -> None:
         if stream_state is None:
             return
-        conn = manager.get_connection(self._node_id)
+        # 优先从 stream 记住的原始连接上移除，避免连接池竞态
+        conn = stream_state._conn
+        if conn is None:
+            conn = manager.get_connection(self._node_id)
         if conn:
             conn.remove_stream(stream_state.stream_id)
 
@@ -120,8 +123,10 @@ class TunnelResponseStream(httpx.AsyncByteStream):
             yield chunk
 
     async def aclose(self) -> None:
-        # 确保 stream 从 connection 的 pending 列表中移除，防止内存泄漏
-        conn = self._manager.get_connection(self._node_id)
+        # 从 stream 记住的原始连接上精确移除，避免连接池竞态
+        conn = self._stream_state._conn
+        if conn is None:
+            conn = self._manager.get_connection(self._node_id)
         if conn:
             conn.remove_stream(self._stream_state.stream_id)