Advance Blender 5.2 web parity through M12-03D

docs/status/M12-02D.md

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+# M12-02D Status
+
+status: done
+task: commit a catalog preview reference only after verified OPFS persistence
+updated: 2026-08-17 America/New_York
+enablingTask: true
+parityStateChange: false
+
+## Scope
+
+The production coordinator first runs the M12-02C pre-decode gate, writes the content-addressed
+preview to OPFS, reads it back, and repeats identity verification. Only then may one IndexedDB
+transaction advance the catalog revision and write both the v2 preview reference and an M12-02D
+head receipt. The receipt binds project, asset, base/current revision, base/current manifest hash,
+preview identity, payload identity, and OPFS path.
+
+The transaction rereads and compares the complete source catalog row before publication. A stale
+revision or changed row returns `REVISION_CONFLICT`; OPFS and transaction faults return
+`STORAGE_TRANSACTION`. An OPFS payload left by a failure is unreferenced, never presented as a
+committed catalog preview.
+
+## Evidence
+
+- `WEB_TEST_PORT=5596 npm --prefix web run test:asset-preview-opfs-commit` passed the artifact unit
+  test 1/1 and the real Chromium OPFS/IndexedDB test 1/1.
+- `BEFORE_OPFS_WRITE`, `AFTER_OPFS_WRITE`, and `AFTER_CATALOG_PUT` faults all preserved the complete
+  revision 7 catalog and left no commit receipt. Only the latter two left an unreferenced payload.
+- Success persisted and reread the 513-byte payload before advancing the catalog to revision 8;
+  closing and reopening IndexedDB reproduced the same preview and receipt and rehashed OPFS bytes.
+- `npm --prefix web run typecheck`, `npm --prefix web run lint`, and `git diff --check` passed.
+
+## Artifact Hashes
+
+- commit coordinator: `36418e480b108eb885b5d8da6633174ed1face1fa62742a64372a45280e727a2`
+- Chromium suite: `043b9b06d4c0275938cc1d4f9837df95f58f281130f3c0f2b90c10540244592e`
+- unit suite: `f489a1d9a4c5fb24a99bce6d31841534c7cf3981b53076a0d9e19d106e9d0d74`
+- manifest: `34fe6c6ab097e58f7b648dd84cb919ecb407a5742e387c513bb3ed53db50eed6`
+- package commands: `7363a8a03cb5f6b1d6bf40d8eabc90b9d48e91aeb4787b175deb4f242c676243`
+
+## Next Task
+
+`M12-02E`: deduplicate identical preview content without allowing different asset metadata to
+overwrite the shared payload.
+
+## Rollback
+
+Remove the OPFS/catalog commit coordinator, Chromium and unit suites, M12-02D manifest, package
+command, and this status entry. Restore M12-02D to pending and `nextTask` to M12-02D. No parity
+ledger rollback is required.