feat: Build comprehensive webhook notification system for event-driven integrations

[kokobutter-web]

Summary

Implements #337 - Build comprehensive webhook notification system for event-driven integrations

Changes

Backend - Delivery Analytics

• Added getWebhookAnalytics() to backend/src/services/webhooks.ts computing success rate, average latency, average payload size, and per-status breakdowns from delivery logs.
• Added GET /webhooks/analytics route.

Backend - Webhook Testing Endpoint

• Added sendWebhookTest() and getSamplePayloads() functions with sample payloads for payment.completed, payment.failed, and payment.disputed events.
• Added POST /webhooks/test and GET /webhooks/test/payloads routes.

Backend - Per-endpoint Rate Limiting

• Added rate-limit map keyed by webhook config URL (60 events/min per endpoint) enforced in enqueueWebhookEvent().
• Added GET /webhooks/rate-limits route exposing current rate limit status.

Frontend

• Added analytics dashboard to frontend/app/dashboard/webhooks/page.tsx showing success rate, avg latency, delivered count, avg payload size, and pending/failed/dead-letter counts.
• Added "Send Test" dialog allowing merchants to send test webhooks with selectable event types.
• Added getAnalytics, sendTest, getSamplePayloads, and getRateLimits methods to the frontend API client.

Acceptance Criteria Coverage

• Webhook registration with secret token generation (existing)
• HMAC-SHA256 signature for payload integrity (existing)
• Retry queue with exponential backoff, max 5 retries (existing)
• Delivery analytics (success rate, latency, payload size)
• Webhook testing endpoint with sample payloads
• Rate limiting per webhook endpoint

[vercel]

Someone is attempting to deploy a commit to the smartdevs17's projects Team on Vercel.

A member of the Team first needs to authorize it.

[Smartdevs17]

⚠️ Merge failed — check CI status.

🤖 Drips Wave Merge Agent