ChannelMessage.sender was used both for display (username) and as the
reply target in Channel::send(). For Telegram, sender is the username
(e.g. "unknown") while send() requires the numeric chat_id, causing
"Bad Request: chat not found" errors.
Add a dedicated reply_to field to ChannelMessage that stores the
channel-specific reply address (Telegram chat_id, Discord channel_id,
Slack channel, etc.). Update all channel implementations and dispatch
code to use reply_to for send/start_typing/stop_typing calls.
This also fixes the same latent bug in Discord and Slack channels where
sender (user ID) was incorrectly passed as the reply target.
Implement Lark/Feishu as a new channel for ZeroClaw (Issue #164).
- Add LarkChannel with Channel trait impl (name, listen, send)
- listen: HTTP server (axum) for event callback with URL verification
(challenge response) and im.message.receive_v1 text message parsing
- send: POST /open-apis/im/v1/messages with tenant_access_token auth
- get_tenant_access_token with caching and auto-refresh on 401
- Allowlist filtering by open_id (same pattern as other channels)
- Add LarkConfig to schema (app_id, app_secret, verification_token, port, allowed_users)
- Register lark in channel list, doctor, and start_channels
- 18 unit tests: config serde, allowlist, channel name, message parsing,
edge cases (unicode, missing fields, invalid JSON, wrong event type)
- Fix pre-existing SchedulerConfig compile error on main
