Add webhook retry queue with exponential backoff

[chigozirim007]

Summary

• Added durable webhook delivery queue via new WebhookDelivery model and migration.
• Updated webhook dispatch flow to enqueue deliveries and attempt first send immediately.
• Added queue processor with retry schedule: 1m, 5m, 30m, 2h, 6h (max 6 attempts total).
• Added cron endpoint to process pending deliveries: GET /api/cron/process-webhooks guarded by CRON_SECRET.
• Added developer APIs:
  • GET /api/routes-d/developers/webhooks/deliveries?webhookId={id}
  • POST /api/routes-d/developers/webhooks/deliveries/[id]/retry for manual retry.
• Added �ercel.json cron schedule to process webhook queue every minute.

Notes

• Could not run prisma generate in this environment due blocked network access to Prisma binaries.

px tsc --noEmit still fails on a pre-existing syntax error in components/DevModeBanner.tsx unrelated to this change.

Closes #254

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Project	Deployment	Actions	Updated (UTC)
lance-pay	Error		Feb 26, 2026 0:36am

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Deployment failed with the following error:

Invalid vercel.json file provided