Advance Blender 5.2 web parity through M12-03D

docs/status/M12-03A.md

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+# M12-03A Status
+
+status: done
+task: inventory append, link, and library override data-blocks and dependency closures
+updated: 2026-08-17 America/New_York
+enablingTask: true
+parityStateChange: false
+
+## Scope
+
+The machine inventory separately records Append, Link, and Library Override entry points,
+selectable data-block roots, non-root ID roles, direct/indirect/transitive/embedded dependency
+classes, terminal ownership actions, and override reference/hierarchy/property-operation fields.
+
+The exact closure is an actual Blender Main ID pointer graph walked by
+`BKE_library_foreach_ID_link`, not a hard-coded Object-to-Mesh table. The inventory therefore
+preserves cross-library and override-only dependency distinctions needed by later ownership and
+invalidation contracts. It does not perform a library mutation or add a parity slice.
+
+## Findings
+
+- Blender 5.2 exposes 36 selectable library data-block collections. Screen and WorkSpace are
+  append-only; Library is source/transitive metadata, while embedded Key IDs follow their owner.
+- Append can keep linked, reuse local, make local, or copy local after classifying direct,
+  indirect, and liboverride-only dependencies. Recursive cross-library localization is explicit.
+- Link retains the source `Library`, direct `ID_TAG_EXTERN`, indirect `ID_TAG_INDIRECT`, and
+  transitive parent-library relationships without localization.
+- Override retains a linked reference alongside a local override and hierarchy root. Its 17 RNA
+  fields cover reference/root flags, property paths, operations, and local/reference subitems.
+- Current Web metadata represents only library source, dependency IDs, and read-only state; eight
+  per-ID ownership, override, and invalidation semantics remain absent and mutation stays blocked.
+
+## Evidence
+
+- `npm --prefix web run test:library-operation-inventory` passed with
+  `roots=36 appendOnly=2 operations=3 overrideFields=17 gaps=8 next=M12-03B`.
+- The checker binds nine Blender/Web source files and one real nested-library fixture by SHA-256,
+  verifies link/append action and dependency-walk tokens, launches Blender 5.2, and compares the
+  actual append/link operator properties, library collections, nested source, and override RNA.
+
+## Artifact Hashes
+
+- inventory: `0dcb16233b52b3c0be2373f489d6bf3c771c9d6564993ff98b5d63dcd322fef7`
+- checker: `1581490d1923578293202d27a1c379eb2a8c5e13be418547d148cf09c6a783fd`
+- package commands: `a7cf339b0cf6fab17ef63e9394b2e540af60327f7bf1f7fe95823d182e0d3e63`
+
+## Next Task
+
+`M12-03B`: define source library ID, owner, read-only state, and invalidation token for all three
+operations.
+
+## Rollback
+
+Remove the library operation inventory, checker, package command, and this status entry. Restore
+M12-03A to pending and the queue to M12-03A. No parity ledger rollback is required.