Migration & Safety Flow

[SorraTheOrc]

Add migration safety for the audit field using migration-runner semantics (dry-run listing, explicit confirm, backup), without requiring doctor-command integration in this item.

Acceptance Criteria

• Migration in src/migrations is idempotent.
• Migration runner dry-run lists pending 20260315-add-audit; confirmed run applies it and creates a backup.

Minimal implementation

• Create migration script in src/migrations and runner wiring.
• Add tests for dry-run listing, confirm application, backup creation, and idempotency.

[SorraTheOrc]

OpenCode

Updated acceptance criteria to remove doctor-command integration requirement and focus on migration-runner behavior (dry-run listing, confirm apply, backup, idempotency). Marked completed/in_review based on existing implemented migration + tests in src/migrations/index.ts and tests/migrations.test.ts.