- New 'webhook' then-action: sends HTTP POST with JSON payload to any
user-configured URL (Gotify, Home Assistant, Slack, n8n, etc.)
- Config: URL, optional custom headers (Key: Value per line with
variable substitution), optional custom message
- Payload includes all event variables as JSON fields
- 15s timeout, errors on 400+ status codes
- Follows exact same pattern as Discord/Pushbullet/Telegram handlers
- Frontend: config fields, config reader, icon, help docs
- Updated changelogs with webhook, M3U fix, orchestrator hardening
Event-triggered automations now receive playlist_id from the triggering event
when the action config doesn't have one set. Fixes silent 'No playlist specified'
failures in Discover/Sync chains. Added debug logging to trace event matching.
