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/global_render_positions.py

@@ -10,7 +10,7 @@ from app.domains.rendering.schemas import (
     GlobalRenderPositionPatch,
     GlobalRenderPositionOut,
 )
-from app.utils.auth import require_admin, get_current_user
+from app.utils.auth import require_global_admin, get_current_user
 
 router = APIRouter(prefix="/render-positions/global", tags=["global-render-positions"])
 
@@ -31,7 +31,7 @@ async def list_global_render_positions(
 async def create_global_render_position(
     body: GlobalRenderPositionCreate,
     db: AsyncSession = Depends(get_db),
-    _user=Depends(require_admin),
+    _user=Depends(require_global_admin),
 ):
     """Create a new global render position (admin only)."""
     pos = GlobalRenderPosition(**body.model_dump())
@@ -46,7 +46,7 @@ async def update_global_render_position(
     pos_id: uuid.UUID,
     body: GlobalRenderPositionPatch,
     db: AsyncSession = Depends(get_db),
-    _user=Depends(require_admin),
+    _user=Depends(require_global_admin),
 ):
     """Update a global render position (admin only)."""
     result = await db.execute(select(GlobalRenderPosition).where(GlobalRenderPosition.id == pos_id))
@@ -64,7 +64,7 @@ async def update_global_render_position(
 async def delete_global_render_position(
     pos_id: uuid.UUID,
     db: AsyncSession = Depends(get_db),
-    _user=Depends(require_admin),
+    _user=Depends(require_global_admin),
 ):
     """Delete a global render position (admin only)."""
     result = await db.execute(select(GlobalRenderPosition).where(GlobalRenderPosition.id == pos_id))