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/domains/admin/dashboard_router.py

@@ -13,7 +13,7 @@ from app.domains.admin.dashboard_service import (
     upsert_user_dashboard_config,
     upsert_tenant_default,
 )
-from app.utils.auth import get_current_user, require_admin
+from app.utils.auth import get_current_user, require_global_admin
 from app.models.user import User
 
 logger = logging.getLogger(__name__)
@@ -107,7 +107,7 @@ async def update_config(
 
 @router.get("/tenant-default", response_model=DashboardConfigResponse)
 async def get_tenant_default(
-    current_user: User = Depends(require_admin),
+    current_user: User = Depends(require_global_admin),
     db: AsyncSession = Depends(get_db),
 ) -> DashboardConfigResponse:
     """Load the tenant-default dashboard widget config (admin only)."""
@@ -132,7 +132,7 @@ async def get_tenant_default(
 @router.put("/tenant-default", response_model=DashboardConfigResponse)
 async def update_tenant_default(
     payload: DashboardConfigPayload,
-    current_user: User = Depends(require_admin),
+    current_user: User = Depends(require_global_admin),
     db: AsyncSession = Depends(get_db),
 ) -> DashboardConfigResponse:
     """Set the tenant-default widget config (admin only)."""