feat(N): workflow pipeline, 3D viewer, worker management, QC tests

- workflow_builder.py: fix broken stubs, add render_order_line_still_task
  (resolves step_path from DB instead of passing order_line_id as step_path)
- domains/rendering/tasks.py: add render_order_line_still_task,
  export_gltf_for_order_line_task, export_blend_for_order_line_task,
  generate_gltf_geometry_task (trimesh STL→GLB, no Blender needed)
- tasks/step_tasks.py: add generate_gltf_geometry_task for CadFile GLB export
- cad router: POST /{id}/generate-gltf-geometry endpoint (admin/PM)
- worker router: GET /celery-workers + POST /scale (docker compose subprocess)
- Dockerfile: pip install -e "[dev]" to enable pytest
- docker-compose.yml: docker socket + compose file mount on backend
- ThreeDViewer.tsx: mode toggle (geometry/production), wireframe, env presets,
  download buttons (GLB + .blend)
- CadPreview.tsx: load gltf_geometry/gltf_production/blend_production assets
  from MediaAsset table and pass URLs to ThreeDViewer
- ProductDetail.tsx: "View 3D" button → /cad/:id, "Generate GLB" button
- media router/service: cad_file_id filter on GET /api/media
- WorkerManagement.tsx: new page with worker status, queue depth, scale controls
- App.tsx + Layout.tsx: /workers route + sidebar link (admin/PM)
- tests: test_rendering_service.py, test_orders_service.py (backend)
- tests: WorkerActivity.test.tsx, WorkerManagement.test.tsx (frontend)

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

backend/app/domains/rendering/workflow_builder.py

@@ -20,6 +20,7 @@ def dispatch_workflow(
         "still": _build_still,
         "turntable": _build_turntable,
         "multi_angle": _build_multi_angle,
+        "still_with_exports": _build_still_with_exports,
     }
     builder = builders.get(workflow_type)
     if not builder:
@@ -30,24 +31,56 @@ def dispatch_workflow(
 
 
 def _build_still(order_line_id: str, params: dict):
-    from app.domains.rendering.tasks import render_still_task
+    """Still render: resolves STEP path from order_line DB record."""
+    from app.domains.rendering.tasks import render_order_line_still_task
     return chain(
-        render_still_task.si(order_line_id, **params)
+        render_order_line_still_task.si(order_line_id, **params)
     )
 
 
 def _build_turntable(order_line_id: str, params: dict):
+    """Turntable animation: requires step_path + output_dir in params."""
     from app.domains.rendering.tasks import render_turntable_task
+    step_path = params.get("step_path")
+    output_dir = params.get("output_dir")
+    if not step_path or not output_dir:
+        raise ValueError(
+            "turntable workflow requires 'step_path' and 'output_dir' in params"
+        )
+    remaining = {k: v for k, v in params.items() if k not in ("step_path", "output_dir")}
     return chain(
-        render_turntable_task.si(order_line_id, **params)
+        render_turntable_task.si(step_path, output_dir, **remaining)
     )
 
 
 def _build_multi_angle(order_line_id: str, params: dict):
-    from app.domains.rendering.tasks import render_still_task
-    angles = params.get("angles", [0, 45, 90])
-    p = {k: v for k, v in params.items() if k != "angles"}
+    """Multi-angle stills: renders the same order_line from multiple rotation_z angles."""
+    from app.domains.rendering.tasks import render_order_line_still_task
+    angles = params.pop("angles", [0, 45, 90])
     return group(
-        render_still_task.si(order_line_id, camera_angle=angle, **p)
+        render_order_line_still_task.si(order_line_id, rotation_z=float(angle), **params)
         for angle in angles
     )
+
+
+def _build_still_with_exports(order_line_id: str, params: dict):
+    """Still render + parallel GLB exports (geometry + production quality).
+
+    Pipeline:
+        render_order_line_still_task → group(
+            export_gltf_for_order_line_task,
+            export_blend_for_order_line_task,
+        )
+    """
+    from app.domains.rendering.tasks import (
+        render_order_line_still_task,
+        export_gltf_for_order_line_task,
+        export_blend_for_order_line_task,
+    )
+    return chain(
+        render_order_line_still_task.si(order_line_id, **params),
+        group(
+            export_gltf_for_order_line_task.si(order_line_id),
+            export_blend_for_order_line_task.si(order_line_id),
+        ),
+    )