Entries that share a schema id are one schema seen by different writers, so the writer lists every id any of them lists, in any
order: C# single-file and directory (CultSchemaCatalogEntry.MergeById), TypeScript and Python. Rust synthesises one entry per id and
has no such merge. An id that one entry owns and another lists as compatible names the owner in Rust, TypeScript, Python and the TS
inspector, as C# already did (own-id-over-compatible-v3). Also: a directory manifest in an unreadable format is the typed refusal
naming it, cultnet-py applies and reports a record under the local schema id, and Rust's error prints its cause once.
Vectors for the Mesh layout discriminator: a nil and an integer at catalog slot 5.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>