- Add WebhookPayloadTemplate model with builtin template support
- Add WebhookTemplateService for template rendering (Mustache, JSON)
- Add WebhookSecretRotationService with grace period handling
- Add WebhookTemplateController and WebhookSecretController API endpoints
- Add WebhookTemplateManager Livewire component for admin UI
- Add CleanupExpiredSecrets console command
- Add BuiltinTemplateType and WebhookTemplateFormat enums
- Add migrations for api tables and secret rotation fields
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>