refactor(P11+P12): codebase hygiene — CLAUDE.md rewrite, type safety, dead code removal

- Rewrite CLAUDE.md to match current 8-service architecture (was 11, 5 deleted)
- Remove all as-any casts in OrderDetail.tsx (9 casts → 0)
- Add cad_parsed_objects/cad_part_materials to OrderItem interface
- Rename require_admin → require_global_admin across 6 router files (22 calls)
- Remove EXPORT_GLB_PRODUCTION enum + generate_gltf_production_task (dead code)
- Remove worker-thumbnail from ALLOWED_SERVICES, replace Flamenco link
- Delete obsolete PLAN.md (1455 lines) and PLAN_REFACTOR.md (1174 lines)
- Fix digit-only USD prim names with p_ prefix

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

backend/app/api/routers/cad.py

@@ -303,34 +303,6 @@ async def generate_gltf_geometry(
     return {"status": "queued", "task_id": task.id, "cad_file_id": str(id)}
 
 
-@router.post("/{id}/generate-gltf-production", status_code=status.HTTP_202_ACCEPTED)
-async def generate_gltf_production(
-    id: uuid.UUID,
-    user: User = Depends(get_current_user),
-    db: AsyncSession = Depends(get_db),
-):
-    """Queue production GLB export (Blender + PBR materials) from a geometry GLB.
-
-    Requires a gltf_geometry MediaAsset to already exist (run generate-gltf-geometry first).
-    Stores result as a MediaAsset with asset_type='gltf_production'.
-    """
-    if not is_privileged(user):
-        raise HTTPException(status_code=403, detail="Insufficient permissions")
-
-    cad = await _get_cad_file(id, db)
-    if not cad.stored_path:
-        raise HTTPException(status_code=404, detail="STEP file not uploaded for this CAD file")
-
-    logger.warning(
-        "generate_gltf_production called for cad %s — "
-        "deprecated: renders now consume usd_master directly",
-        id,
-    )
-    from app.tasks.step_tasks import generate_gltf_production_task
-    task = generate_gltf_production_task.delay(str(id))
-    return {"status": "queued", "task_id": task.id, "cad_file_id": str(id)}
-
-
 @router.post(
     "/{id}/regenerate-thumbnail",
     status_code=status.HTTP_202_ACCEPTED,