Migration

Map current readers, writers, data shape, compatibility window, and ownership before editing.

• Define forward path and rollback path.
• Preserve existing data; make destructive steps explicit and separately authorized.
• Keep mixed-version operation safe where rollout can overlap.
• Sequence expand, migrate, verify, then contract when applicable.
• Make retries idempotent and partial failure observable.
• Verify old and new paths at required transition stages.

Stop after requested stage passes; do not perform later destructive contraction implicitly.