Updated docs for all bundled plugins to reflect:
- Plugins are bundled with Clawdbot
- Dependencies auto-install on first load when enabled
- npm install is an alternative, not required
- Simplified setup steps
Updated channels:
- line, matrix, mattermost, msteams, nextcloud-talk, nostr, zalo, zalouser
Updated plugins:
- voice-call, zalouser
Add Mattermost as a supported messaging channel with bot API and WebSocket integration. Includes channel state tracking (tint, summary, details), multi-account support, and delivery target routing. Update documentation and tests to include Mattermost alongside existing channels.
