fix: 直接上传multipart超时 — connect timeout 10s→120s

requests/urllib3 发送 multipart body 期间 socket timeout 取的是
connect timeout 值而非 read timeout，跨境 1.4MB/s 下 17MB 视频需
~117s，原 10s 上限导致 100% 超时重试耗尽标记 FAILED。实测 task
50/51 修复后直接上传成功。

fam-core/src/fam_core/dispatcher/dispatcher.py

@@ -275,7 +275,12 @@ class Dispatcher:
             self._dispatch_direct(task, payload, upload_path)
 
     def _dispatch_direct(self, task, payload, video_path):
-        """小文件直接上传至 /enqueue"""
+        """小文件直接上传至 /enqueue
+
+        注意 timeout 第一参数: urllib3 发送 multipart body 期间 socket
+        timeout 取的是 connect timeout 值（实测传 60s 则 60s 整超时），
+        而非 read timeout——跨境 1.4MB/s 下 17MB 需 ~12s，必须给足。
+        """
         task_id = task['task_id']
         try:
             with open(video_path, 'rb') as fh:
@@ -283,7 +288,7 @@ class Dispatcher:
                     self.edge_url,
                     data=payload,
                     files={'video': (os.path.basename(video_path), fh, 'video/mp4')},
-                    timeout=(10, 300)
+                    timeout=(120, 300)
                 )
         except requests.RequestException as e:
             logger.error(f"[task_id={task_id}] 上传失败: {e}")