Add comprehensive MQTT and webhook integration for Home Assistant and external services:
MQTT Client (internal/mqtt/client.go):
- Optional MQTT client with exponential backoff reconnect (5s-120s)
- TLS support for mqtts:// connections
- Home Assistant auto-discovery for persons, zones, fall detection, system health, system mode
- Topic structure: spaxel/{mothership_id}/person/{id}/presence, zone/{id}/occupancy, etc.
- LWT (Last Will and Testament) for availability
- Dynamic configuration updates via API
- Retained messages for presence and occupancy states
MQTT Publisher (internal/mqtt/publisher.go):
- Event bus subscriber publishing zone entry/exit, fall alerts, anomalies
- Person presence tracking across zones with home/not_home states
- Zone occupancy counting with occupants list
- Periodic system health publishing (60s interval)
- HA discovery methods for all entity types
- Person and zone discovery removal on delete
System Webhook (internal/webhook/publisher.go):
- Single webhook URL receiving all events with X-Spaxel-Event header
- JSON payload with event_type, timestamp, zone, person, blob_id, severity, detail
- Retry policy: one retry after 30s on 5xx errors
- Test webhook endpoint for configuration verification
API Integration Handler (internal/api/integrations.go):
- GET/POST /api/settings/integration for MQTT and webhook configuration
- POST /api/settings/integration/test for testing connections
- Settings persisted in database settings table
- Integration with existing MQTTClient and WebhookPublisher interfaces
Dashboard Integration UI (dashboard/integrations.html, js/integrations.js):
- Settings panel with MQTT broker URL, username, password (masked), TLS toggle
- Discovery prefix configuration
- Test Connection and Publish Discovery buttons
- System webhook URL configuration with enable toggle
- Connection status indicator with error messages
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
