Interface EnsureSchemaOptions

Skip re-running when the same schema has already been applied to the same set of shards in this process. DDL is idempotent (IF NOT EXISTS), so this is a latency optimization, not a correctness gate.

Version value paired with versionKey (default: '1')

KV key holding an applied-schema version marker. When the stored value equals version, schema creation is skipped entirely; otherwise the schema runs and the marker is written. Persists across processes.