Fix wallet deletion audit issue

[Bug-Hunter-X]

Overview

This PR addresses issue #181 Missing Wallet deletion audit. It adds audit logging for wallet unlinking to ensure all wallet deletions are recorded in the audit trail.
closes #181

Objectives

• Implement the missing audit logging when a wallet is unlinked.
• Add unit tests verifying the audit entry is created.
• Verify the implementation against existing protocol invariants and ensure no regressions.

Problem Context

During a recent audit it was discovered that wallet unlinking operations were not being logged, leaving a gap in traceability and security compliance.

Technical Scope

• Updated src/identity/identity.service.ts to call AuditTrailService.log with a WALLET_UNLINKED action.
• Added WALLET_UNLINKED to AuditActionType enum in src/audit/entities/audit-log.entity.ts.
• Created unit test src/identity/identity.service.spec.ts to assert the audit log call.

Acceptance Criteria

• Implementation: Wallet unlinking logs a WALLET_UNLINKED audit entry with appropriate metadata (wallet ID, user ID, address, description).
• Tests: Unit test passes confirming the audit service is called.
• No regressions: Existing tests continue to pass, and the application builds successfully.

Verification

• npm run lint ✅ (existing repo warnings only)
• npm run typecheck ✅
• npm test -- src/identity/identity.service.spec.ts --runInBand ✅
• npm run build ✅

Security / Integrity Considerations

• Audit entries include user ID and wallet address, but no sensitive private keys.
• Logs are stored with standard audit security controls.

References

• Internal Ref #BE-181

Labels

• backend, stellar-wave, complexity-medium

[dDevAhmed]

resolve conflicts @Bug-Hunter-X

[Bug-Hunter-X]

@dDevAhmed done sir.