v5.4.1

Patch release — LOCO eigen-cache review follow-ups (no API change).

Changed

• LOCO eigen-cache invalidation diagnostics: eigen_cache_is_valid now reports a malformed manifest (parses but has no cache_key — e.g. an old-schema or truncated file) distinctly from a real input change, and enforces the manifest schema_version explicitly before the key compare instead of relying only on its presence in the hashed payload — a schema bump now invalidates all prior caches with a clear log reason. The manifest is fsync'd before its atomic rename so a crash cannot leave a parseable-but-garbage manifest, and corrupt-vs-unreadable manifests log distinct warnings. Manifest and components payloads are now typed via TypedDict (EigenCacheComponents, EigenCacheManifest).

Docs

• Corrected the "recomputed once" claim: a cache written before the manifest existed is rejected and recomputed on every read run until regenerated with -eigen. Added schema_version to the listed cache determinants.