Add retry logic with exponential backoff to webhookDeliveryQueue

[Kingsman-99]

Description

src/lib/webhookDeliveryQueue.ts delivers webhook events to configured endpoints but makes no retry attempt when a delivery fails. A single network hiccup permanently drops the event, causing silent data loss for webhook consumers.

Acceptance Criteria

• Failed deliveries are retried up to 3 times with exponential backoff (1s, 2s, 4s delays)
• After 3 failed attempts the event is moved to a dead-letter list accessible via a getFailedDeliveries(): WebhookEvent[] export
• Successful delivery on any retry clears the event from the retry queue
• Unit tests: first attempt succeeds (no retry), second attempt succeeds (one retry), all 3 retries fail (event in dead-letter list)
• Existing tests continue to pass

Context

• Target file: src/lib/webhookDeliveryQueue.ts
• Use setTimeout-based delays; no new dependencies

[Iker2522]

Hi, I’d like to take this task. I can add the retry logic with exponential backoff, dead-letter handling, and the required unit tests while keeping the existing behavior and avoiding new dependencies.

[Ranjeet2063]

Hi maintainers, I'd love to take this on!

Execution Plan for Add retry logic with exponential backoff to webhookDeliveryQueue:

• Clean Implementation: Deliver an idiomatic solution for Add retry logic with exponential backoff to webhookDeliveryQueue adhering strictly to Stellar-split/split-app's architecture.
• Automated Tests: Provide full test coverage asserting both edge cases and core workflows.
• Clean Git Hygiene: Atomic conventional commits with zero merge conflicts.

Why assign me?

• Proven Proof-of-Work: Implement real-time PaymentProgress updates #1 contributor on Mova Store (28 merged Web3 PRs) and official ElizaOS contributor.
• Fast Turnaround: Dedicated to shipping a tested, production-grade PR within 12–24 hours.
• Zero Maintainer Burden: Self-documenting code with green CI and tests included so you don't spend time debugging.

Looking forward to clearing this off your backlog—please assign to me!