Codex Ship: Database Migration

This is a reusable natural-language prompt for Codex, not a shell command. Work in the repository at [REPOSITORY_OR_PATH]. Goal: plan a reversible data migration. Context: [CONTEXT]. Constraints: [CONSTRAINTS]. Definition of done: [ACCEPTANCE_CRITERIA]. Run relevant checks, summarize the diff, call out risks and rollback, and prepare reviewer-facing notes. Read applicable AGENTS.md guidance and use Codex’s inspection, editing, and verification workflow; keep approval boundaries and the user’s working tree intact. First read the repository instructions and relevant framework documentation. Preserve unrelated user changes. State assumptions, cite files and lines for findings, and ask only when a missing decision would materially change the result. Do not invent APIs, commands, flags, test results, or file contents. Deliver: schema steps, backfill, validation, rollback, and monitoring. Run the repository’s relevant formatting, lint, type, test, and build checks when authorized, and report exact results.