Refactor the Channel trait to accept a SendMessage struct instead of
separate message and recipient string parameters. This enables passing
additional metadata like email subjects.
Changes:
- Add SendMessage struct with content, recipient, and optional subject
- Update Channel::send() signature to accept &SendMessage
- Update all 12 channel implementations
- Update call sites in channels/mod.rs and gateway/mod.rs
Subject field usage:
- Email: uses subject for email subject line
- DingTalk: uses subject as markdown message title
- All others: ignore subject (no native platform support)
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 DingTalk messaging channel using the official Stream Mode
WebSocket protocol with per-message session webhook replies.
- Add DingTalkChannel with send/listen/health_check support
- Add DingTalkConfig (client_id, client_secret, allowed_users)
- Integrate with onboard wizard, integrations registry, and channel
list/doctor commands
- Include unit tests for user allowlist rules and config serialization
