feat: implement webhook action firing & fault tolerance for automations
Backend: HTTP client with 5s timeout, fire-and-forget webhook delivery,
4xx disables trigger with error message, 5xx/timeout increments error count,
test endpoint, enable/disable endpoints, webhook_log audit table,
WebSocket alert broadcasting on trigger errors.
Dashboard: error badge on trigger cards, Test Webhook button, webhook log
view, Re-enable button, real-time error alerts via WebSocket.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
e74834a3bf