Add concurrency tests for migration safety executor rollback path

[thlpkee20-wq]

Description

The migration safety subsystem under src/db/migrations/safety/ (executor.ts, rollback.ts, validation.ts, accessControl.ts) has a single migrationSafety.test.ts, but the rollback and access-control branches need dedicated coverage to ensure a failed migration cleanly reverts and is auditable. Add focused tests for the executor's failure/rollback path.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: src/db/migrations/safety/executor.ts, src/db/migrations/safety/rollback.ts, src/db/migrations/safety/audit.ts
• A failed step must trigger rollback and emit an audit record

Suggested execution

• Fork the repo and create a branch
• git checkout -b test/migration-rollback-coverage
• Implement changes
  • Simulate a mid-migration failure and assert rollback is invoked
  • Assert the audit log records the failure and revert
  • Assert access control rejects unauthorized migration execution
• Validate security and correctness assumptions

Test and commit

• Run tests
  • npm test
• Cover edge cases
  • Rollback itself fails, partial step applied, concurrent migration attempt blocked
• Include test output and notes

Example commit message

test: cover migration executor rollback and access control

Guidelines

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

[WHIZAB4TECH]

@WHIZAB4TECH has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

"I am eager to contribute to this project. As a full-stack developer specializing in secure smart contract architecture, my background in building scalable backends and auditing blockchain security aligns perfectly with your requirements. I am confident I can add immediate value to the team."

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