chore: cleanup #6 #8 #9 — delete debug dir, rename glbUrl prop, sync docs

- delete renderproblems_tmp/ (7 debug images + USD test files, orphaned)
- rename ThreeDViewer prop geometryGltfUrl → glbUrl; update CadPreview.tsx
  caller (productionGltfUrl distinction was never needed, only one GLB type)
- plan.md: mark all 4 cinematic tasks [x] (all implemented + seeded in 070)
- 0001-step-to-usd: mark Phase 4 ThreeDViewer acceptance gates [x] (P4 done)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plan.md

@@ -6,7 +6,7 @@ Add a new render type: a 20-second cinematic product highlight video with proced
 
 ## Tasks
 
-### [ ] Task 1: Cinematic Blender script
+### [x] Task 1: Cinematic Blender script
 
 - **File**: `render-worker/scripts/cinematic_render.py` (new)
 - **What**: Blender Python script that:
@@ -36,7 +36,7 @@ Add a new render type: a 20-second cinematic product highlight video with proced
 - **Acceptance gate**: Script renders a 20s MP4 from a STEP file
 - **Dependencies**: None
 
-### [ ] Task 2: Render service function
+### [x] Task 2: Render service function
 
 - **File**: `backend/app/services/render_blender.py`
 - **What**: Add `render_cinematic_to_file()` function with same signature as `render_turntable_to_file()` but:
@@ -47,7 +47,7 @@ Add a new render type: a 20-second cinematic product highlight video with proced
 - **Acceptance gate**: Function callable, builds correct subprocess command
 - **Dependencies**: Task 1
 
-### [ ] Task 3: Pipeline integration
+### [x] Task 3: Pipeline integration
 
 - **File**: `backend/app/domains/pipeline/tasks/render_order_line.py`
 - **What**: In the render task, detect when output type has a cinematic flag. Add a check:
@@ -56,7 +56,7 @@ Add a new render type: a 20-second cinematic product highlight video with proced
 - **Acceptance gate**: Order line with cinematic output type renders via the new script
 - **Dependencies**: Task 2
 
-### [ ] Task 4: Output type + test
+### [x] Task 4: Output type + test
 
 - **What**: Create the "Cinematic Highlight" output type via API:
   ```json