Add get_check_in_timestamp read-only accessor for milestone check-in time in accountability_vault

[1nonlypiece]

Add get_check_in_timestamp read-only accessor for milestone check-in time in accountability_vault

Description

check_in in contracts/accountability_vault/src/lib.rs stores DataKey::CheckIn(index) -> timestamp but no public accessor exposes it. The backend ETL (src/services/etlWorker.ts) currently has no way to read the recorded check-in time without scanning events. Add a get_check_in_timestamp(index: u32) -> Option<u64> returning the stored value or None if not yet checked in.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Add get_check_in_timestamp to contracts/accountability_vault/src/lib.rs
• Return Option<u64> keyed by DataKey::CheckIn(index)
• Add read tests in contracts/accountability_vault/src/test.rs
• Document the function in contracts/README.md

Suggested execution

• Fork the repo and create a branch
• git checkout -b feat/get-check-in-timestamp
• Implement changes
  • Modify contracts/accountability_vault/src/lib.rs
  • Add tests in contracts/accountability_vault/src/test.rs
  • Update contracts/README.md
  • Add index bounds check
• Test and commit
  • Run tests, cover edge cases
  • Include test output and notes

Example commit message

feat: add get_check_in_timestamp read accessor

Guidelines

• Minimum 95 percent test coverage
• Clear documentation
• Timeframe: 96 hours

[BigMick03]

@BigMick03 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Please I will like to work on this issue for you.

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[drips-wave]

Congratulations, @BigMick03! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

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