* fix(channels): surface WeCom WebSocket connection failures (#2000)
The WeCom channel started the SDK connection with a fire-and-forget
asyncio task and never inspected its result, so connection failures
(e.g. the gateway WebSocket handshake to wss://openws.work.weixin.qq.com
failing) were silently swallowed: the channel still logged "started",
SDK error/disconnected events went unobserved, and the connect task
produced "Task exception was never retrieved" noise.
Monitor the connect task with a done-callback that logs a clear,
actionable error (and stays silent on cancellation), and subscribe to
the SDK's error/disconnected events so failures become visible in
DeerFlow's own logs.
* style(channels): apply ruff format to wecom.py
Collapse the multiline log message onto a single line to satisfy the
CI ruff formatter (lint-backend was failing on format --check).
* fix(channels): log WeCom disconnect reason when SDK provides one
Address review feedback: _on_ws_disconnected now includes the first
event arg (e.g. reason/context) in the warning instead of discarding
it, so disconnect causes are visible in logs.
c91dacc8e2