iven
5eeabd1f30
feat(saas): add webhook event notification system (@unplugged)
Webhook infrastructure for external event notifications:
- SQL migration: webhook_subscriptions + webhook_deliveries tables
- Types: CreateWebhookRequest, UpdateWebhookRequest, WebhookDelivery
- Service: CRUD operations + trigger_webhooks + HMAC-SHA256 signing
- Handlers: REST API endpoints (CRUD + delivery logs)
- Worker: WebhookDeliveryWorker with exponential retry (max 3)
NOT YET INTEGRATED: needs mod registration in lib.rs + workers/mod.rs,
hmac crate dependency, and route mounting. Code is ready for future
integration after stabilization phase completes.