Variable SOURCE_SCHEMA_V2_KINDConst Experimental

SOURCE_SCHEMA_V2_KIND: "honua.source-schema" = ...

Lightweight SourceSchemaV2 envelope checks for generic consumers.

This module intentionally does not validate schema contents or recompute the fingerprint. Full validation belongs to the focused /source-schema ingestion and cache boundaries. Generic discovery uses this only as a bounded transport-envelope check; it does not establish trusted identity.