omd:component-harvest — catalog write safety gate

CORE_V2_CATALOG_WRITE_BLOCKED

Do not rewrite a reference section, legacy frontmatter token block, mirror, or quality marker. The current public catalog is dual-read source material, while all future writers must be graph-backed Core v2. Reusing the retired section and frontmatter mutation path would create a new legacy authority and can silently lose provenance.

Report that component harvesting is temporarily read-only. Evidence collection may be proposed separately, but no catalog bytes may change until a canonical catalog graph/evidence writer, migrated readers, and a provider-free dropped_segments=0 migration gate ship together.