refactor(ntfs): share the producer-owned record identity verdict

Co-authored-by: gensokyo-dev <342580529+gensokyo-dev@users.noreply.github.com>

docs/specs/native/ntfs-mft/plan.md

@@ -63,3 +63,8 @@ entries and explicit discovered omissions. This adds no volume reads, path
 reconstruction, nonresident payload recovery or target execution. Real extension
 captures and Windows-host execution remain unverified; source-built fixtures
 exercise reference ownership, malformed prefixes, cycles and resource bounds.
+
+
+Journal and extension joins share `hasVerifiedMftRecordIdentity` at the MFT
+owner. It consumes parsed sequence, slot verdict, extent and fixup facts; each
+consumer keeps its separate base-versus-extension ownership rule.