feat: implement Dead-Letter Queue (DLQ) infrastructure and management…

[muhsar27]

… service

Summary

Implements a dead-letter queue (DLQ) processing and administrative management system for BullMQ jobs across background workers (transaction execution, webhook delivery, risk analysis, and notifications) with secured RBAC-guarded administrative endpoints to inspect, retry, and purge failed jobs.

Type of change

• Bug fix
• New feature
• Refactor / cleanup
• Documentation
• CI / tooling

Related issue

Closes #98

Why this change is needed

When background workers exhaust maximum retry attempts on transient or permanent failures (such as third-party API outages, invalid payloads, or network timeouts), jobs should be routed to a designated Dead-Letter Queue structure for forensic debugging, audit ledgering, and administrative remediation. Without dedicated DLQ tooling, failed jobs remain opaque or require manual database/Redis interventions. This feature provides a centralized DlqProcessor and a secured DlqController allowing administrators to inspect full error payloads/stack traces, retry failed jobs individually or in bulk, and purge obsolete records under strict OWNER / ADMIN role access control.

Checklist

• npm run build passes
• npm test passes
• npm run lint passes
• npm run typecheck passes
• No secrets added to tracked files
• PR description explains the why, not just the what

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[mergekeeper]

MergeKeeper review

Scope: in scope for linked issue #98.
Verdict: clean

The pull request correctly implements the BullMQ dead-letter queue processor, administrative DLQ endpoints, associated DTOs, and unit tests as required by issue #98.

Reviewed commit: aad03352c8fa17936c4cf5c1ad91da2829f9ab40.
CI and merge eligibility are checked separately.

[mergekeeper]

MergeKeeper review unavailable

AI provider review response did not contain valid JSON

No approval or merge action was taken.

[mergekeeper]

MergeKeeper merge status

Status: blocked
PR state: open
Mergeability: mergeable
Checked commit: 8c9c9ec58f84a63609483ce0c40058007c8671a0.

Reason:
GitHub pull request merge request failed with 405: 4 of 4 required status checks are expected.

Next steps:
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1. Wait for the check to pass, or fix the underlying failure.
2. To let an explicit override bypass this check going forward, add the MergeKeeper GitHub App as a Bypass actor on the ruleset (Settings → Rules → Rulesets → the ruleset → Bypass list).

[mergekeeper]

Approved

Successfully implemented the BullMQ dead-letter queue processor, administrative DLQ management service, and RBAC-secured endpoints with complete unit test coverage.

[mergekeeper]

Approved

The pull request correctly implements the BullMQ dead-letter queue processor, administrative DLQ endpoints, associated DTOs, and unit tests as required by issue #98.

[mergekeeper]

Merged

Merged with squash.