Ledger-export retention labels reflecting legal-hold status per period

[thlpkee20-wq]

Description

Some ledger periods are under legal hold and must not be purged even after retention. Add retention labels per period with legal-hold override and a purge worker that respects labels.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: src/services/auditPurgeService.ts
• Legal-hold add/remove dual-controlled

Suggested execution

• Fork the repo and create a branch
• git checkout -b feat/ledger-legal-hold-labels
• Implement changes
  • Add retention_labels table
  • Extend purge to skip held periods
  • Emit purge.skipped_hold counter
• Validate security and correctness assumptions

Test and commit

• Run tests
  • npm test
• Cover edge cases
  • Hold removed re-enters purge on next cycle only
• Include test output and notes

Example commit message

feat: retention labels with legal-hold override

Guidelines

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