Record the tmp/npc-parts working-set layout decision

TODO.md

@@ -49,9 +49,11 @@ the rest of §C remains the broad review checklist.
       prototype detail unless a separate contract decision approves it.
       Recorded in `docs/3d-model-review.md` §Baseline inventory and
       `docs/blender-assets.md` §Frozen fallback boundary.
-- [ ] Choose a local working-set layout: `tmp/npc-parts/<variant>/` (gitignored) for part `.blend`
+- [x] Choose a local working-set layout: `tmp/npc-parts/<variant>/` (gitignored) for part `.blend`
       and preview GLBs; only the assembled character GLBs, AO/maps, manifest and review sheets are
       committed. Do not add a new committed `.blend` source tree without a docs/ADR decision.
+      Recorded in `docs/3d-model-review.md` §Working-set layout and
+      `docs/asset-tooling.md` §Recommended part-workflow.
 
 ### 2. Local part pipeline