Add audit log service for sensitive admin and contract operations

[Chucks1093]

Summary

Implement a centralised audit log service that records all sensitive admin actions and contract operations with actor, action, target, and timestamp for compliance purposes.

Scope

• Audit log table with actor wallet, action type, target entity, payload snapshot, and timestamp
• Log entries created for: deprecation, multi-sig actions, role changes, suspensions, freeze operations
• GET /admin/audit-log endpoint with filter by action type and date range
• Immutable records — no update or delete endpoints
• Paginated with cursor for large log volumes

Acceptance Criteria

• All defined sensitive operations create an audit log entry
• Audit log endpoint returns correct entries for applied filters
• No update or delete routes exist for audit records
• Pagination cursor works correctly on large datasets
• Admin-only access enforced on the endpoint

ETA

12 hours

[Danitello123]

@Danitello123 has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

I’m a smart contract and full-stack developer who turns complex ideas into secure, production-ready blockchain code.
With strong skills in Rust and Solidity, I build systems that are fast, safe, and built to last.
My experience with the Stellar SDK lets me ship real-world Web3 solutions that actually move value

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[eischideraa-unn]

@eischideraa-unn has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

Hello Maintainer, I can work on this issue, kindly assign

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[gospeltout]

@gospeltout has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

I’d love to work on this issue

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Congratulations, @gospeltout! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on September 30, 2026.

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox!

@gospeltout's PR #958 was approved and merged by @Chucks1093.

🏆 @gospeltout: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (105 total points). Track your full progress on GrantFox.

👏 Great work, @gospeltout! Keep contributing to accesslayerorg.

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This issue has been completed by @gospeltout as part of the Stellar Wave Program's 9th Wave 🥳

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