feat: add Mattermost notifications to Backrest via Shoutrrr hooks
Added global notification hook for all backup operations (backup, prune, check)
using Shoutrrr with Mattermost webhook.
Configuration:
- Hook ID: mattermost-notifications
- Conditions: * (all operations)
- Shoutrrr URL: mattermost://mattermost.pivoine.art/nxsqk4x86jr9bgniheaksem8qy
- Template: Shows operation type, plan/repo ID, status, and errors
Notifications will be sent for:
- All backup operations (17 daily backup plans)
- Weekly prune operations (Sundays at 2 AM)
- Weekly check operations (Sundays at 3 AM)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>