- Relocate keydb.cfg parser into keydb_format.rs (libfreemkv no longer knows keydb); add 100% parse (mkb_version/volume_size/is_uhd, revoked_at_mkb) + helper API (get_uk/get_uks/get_vid/host_certs(mkb)). - KeydbSource/OnlineSource/MultiSource -> get_uk(ctx); MultiSource host_certs union; KAT-proven derivation parity. NumberedUnitKey alias. clippy clean.