Implements the message:received hook event that fires when a user message
is received, before processing. This enables hooks to:
- Track user activity in real-time
- Update state files without polling
- React to incoming messages
Changes:
- Add 'message' to InternalHookEventType union
- Fire message:received event in dispatchInboundMessage()
- Event fires async to avoid blocking message processing
- Include context: senderId, channel, messageBody (truncated), timestamp, cfg
New bundled hook:
- activity-tracker: Updates heartbeat-state.json on every user message
- Sets lastUserMessage to current timestamp
- Sets backupActive=true to enable hourly backups
- Enables session-backup hook to work without polling
Tests:
- message-received.test.ts: Tests for the new hook event
Docs:
- Updated hooks.md to document message:received event
- Moved from 'Future Events' to 'Message Events' section
