Advance Blender 5.2 web parity through M12-03D

docs/status/M12-03C.md

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+# M12-03C Status
+
+status: done
+task: create a desktop single-Object append fixture and stable dependency mapping
+updated: 2026-08-17 America/New_York
+enablingTask: true
+parityStateChange: false
+
+## Scope
+
+Blender 5.2 creates a source library containing one Object whose dependency closure is one Mesh,
+one Material, and one packed Image. A clean desktop Main appends only the Object, saves the target,
+reopens it, and exports the same canonical graph before and after reopen.
+
+The fixture records stable source-to-local mappings, ownership, read-only state, dependency edges,
+geometry/UV/material structure, and packed-image metadata and Float32 pixel SHA-256. Container hashes
+remain session-bound Blender artifacts; the canonical semantic report must reproduce exactly.
+
+## Evidence
+
+- `npm --prefix web run test:library-append-desktop` passed.
+- The generator appended one selected Object and resolved four stable local IDs with three dependency
+  edges.
+- Object, Mesh, Material, and Image all have null library pointers, no library override, writable
+  `LOCAL_MAIN` ownership, and identical source/local stable names.
+- Save/reopen preserved 4 vertices, 4 edges, 1 polygon, 4 loops, `UVMap`, the material slot, packed
+  2x2 sRGB RGBA image metadata, and Float32 pixel SHA-256
+  `6f0f8c231d65149e69e6ed12d370bcfa095ef90adc202065492ea8c8ef17e45a`.
+- A new temporary source/target pair reproduced the canonical report after normalizing only the
+  session-bound `.blend` container hashes.
+
+## Artifact Hashes
+
+- generator: `b9d8e3bd24966b0d7d419382d7ef0b35ae8def9ee2c2236dfd3ad1a90aebe66f`
+- checker: `6f8cc0d51be19423cf6fb7203c3c16f8d27e0fbb3b5b357bad5dec6c5ceb432d`
+- source `.blend`: `5b60d02926efd588a6ca300ba31414cdf37dbc48786c17b383a70319057c0606`
+- target `.blend`: `5cde4927f47e33f0338de38184ce5ba971825fcefd1d8dc6feb48d41a6cdb60c`
+- desktop report: `b1d7b8b9e832d18d69081f63981062800e0f00f0c9aec025b18274510ed76e2a`
+- manifest: `cbfbd8c919125108334dd24925b9ef8e69880983515e56841e6ead4a2b182aed`
+- package commands: `b68f2bce48fcd42e4cc1399b47ba33c35495248a6c0405c2280b5b73e3ce581a`
+
+## Next Task
+
+`M12-03D`: append the same closure into WASM Main with one transaction and local ownership.
+
+## Rollback
+
+Remove the desktop append generator/checker, source and target fixtures, golden report/manifest,
+package command, and this status entry. Restore M12-03C to pending and the queue to M12-03C. No
+parity ledger rollback is required.