fix(feishu): add extra_ua_tags=["channel"] to FeishuWSClient for group @mention delivery

[luxuguang-leo]

Problem

Group @mention messages are not delivered over WebSocket transport.
The Feishu server silently drops group events because the WebSocket
connection was not tagged as a "channel" connection.

Root Cause

FeishuWSClient was created without any UA signaling tag. The server
defaulted to basic DM-only push mode and never sent group @mention events.

Fix

Added extra_ua_tags=["channel"] to the FeishuWSClient constructor call
in _connect_websocket(). This tells the Feishu server to use the Channel
protocol, which enables group-message routing in addition to P2P DM.

The native lark_oapi.channel.FeishuChannel uses the same mechanism
internally (verified against lark_oapi source).

Fixes #50656

Testing

• New regression test: test_connect_websocket_sets_channel_ua_tag
• All 206 existing feishu tests pass

References

• https://open.feishu.cn/document/uAjLw4CM/ukTMukTMukTM/developer-verification/channel-sdk-introduction

[alt-glitch]

This was generated by AI during triage.

Fix PR for #50656 (Feishu group @mention messages not delivered over WebSocket). The extra_ua_tags=["channel"] mechanism is distinct from the require_mention/channel_prompts config PRs in this area.

[leididi]

I successfully used this method to get the AI to fix the Lark group chat function. Please release it in the latest version as soon as possible. Thank you.

[luxuguang-leo]

Quick check-in on this one. Same situation as my other PRs — the check suites are stuck at action_required, so CI hasn't run yet. Is there anything else needed on this PR, or any additional changes you'd like to see before the approach can move forward?

This fixes group @mention delivery over WebSocket on Feishu — leididi mentioned it resolved the issue. Happy to make adjustments if needed.

[teknium1]

Merged via PR #61770. Your Feishu Channel signaling fix was cherry-picked onto current main, the shipped SDK dependency was upgraded to support the new constructor argument, and real SDK compatibility coverage was added. Your authorship is preserved in git history. Thank you.