TransitiveCompatibility

Transitive compatibility over an append-only published history (design §5).

Persisted data outlives code: a stored payload may have been written by any previously published schema version, so the current schema must stay compatible with the whole history — Confluent's *_TRANSITIVE semantics — not merely the latest version. This checks the current schema against every published version and aggregates the findings (deduplicated), so a break against an old version is caught even when the newest version looks fine.