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>

frontend/src/__tests__/pages/WorkerActivity.test.tsx

@@ -0,0 +1,70 @@
+import { describe, test, expect } from 'vitest'
+
+describe('WorkerActivity Page', () => {
+  test('page module is importable', async () => {
+    const module = await import('../../pages/WorkerActivity')
+    expect(module.default).toBeDefined()
+  })
+})
+
+describe('worker API types', () => {
+  test('WorkerActivity interface shape', async () => {
+    // Type-level check: the interface must have the right keys
+    const activity = {
+      cad_processing: [],
+      active_count: 0,
+      failed_count: 0,
+      render_jobs: [],
+      render_active_count: 0,
+      render_failed_count: 0,
+    }
+    expect(activity.cad_processing).toBeInstanceOf(Array)
+    expect(typeof activity.active_count).toBe('number')
+  })
+
+  test('CeleryWorker interface shape', () => {
+    const worker = {
+      name: 'celery@worker1',
+      queues: ['thumbnail_rendering'],
+      active_task_count: 2,
+      active_tasks: [{ name: 'render_still_task', id: 'abc' }],
+      total_tasks_processed: { render_still_task: 42 },
+    }
+    expect(worker.queues).toContain('thumbnail_rendering')
+    expect(worker.active_tasks).toHaveLength(1)
+  })
+
+  test('QueueStatus interface shape', () => {
+    const qs = {
+      queue_depths: { step_processing: 3, thumbnail_rendering: 0 },
+      pending_count: 3,
+      active: [],
+      reserved: [],
+      pending: [],
+    }
+    expect(qs.queue_depths).toHaveProperty('step_processing')
+    expect(qs.pending_count).toBe(3)
+  })
+})
+
+describe('worker API functions', () => {
+  test('getWorkerActivity is a function', async () => {
+    const { getWorkerActivity } = await import('../../api/worker')
+    expect(typeof getWorkerActivity).toBe('function')
+  })
+
+  test('getCeleryWorkers is a function', async () => {
+    const { getCeleryWorkers } = await import('../../api/worker')
+    expect(typeof getCeleryWorkers).toBe('function')
+  })
+
+  test('scaleWorkers is a function', async () => {
+    const { scaleWorkers } = await import('../../api/worker')
+    expect(typeof scaleWorkers).toBe('function')
+  })
+
+  test('getQueueStatus is a function', async () => {
+    const { getQueueStatus } = await import('../../api/worker')
+    expect(typeof getQueueStatus).toBe('function')
+  })
+})

frontend/src/__tests__/pages/WorkerManagement.test.tsx

@@ -0,0 +1,67 @@
+import { describe, test, expect } from 'vitest'
+
+describe('WorkerManagement Page', () => {
+  test('page module is importable', async () => {
+    const module = await import('../../pages/WorkerManagement')
+    expect(module.default).toBeDefined()
+  })
+})
+
+describe('media API', () => {
+  test('getMediaAssets is a function', async () => {
+    const { getMediaAssets } = await import('../../api/media')
+    expect(typeof getMediaAssets).toBe('function')
+  })
+
+  test('MediaFilter supports cad_file_id', () => {
+    // Type-level check: build a filter with cad_file_id
+    const filter = { cad_file_id: 'some-uuid', asset_type: 'gltf_geometry' as const }
+    expect(filter.cad_file_id).toBe('some-uuid')
+  })
+
+  test('MediaAsset interface has all required fields', () => {
+    const asset = {
+      id: 'uuid',
+      tenant_id: null,
+      product_id: null,
+      cad_file_id: null,
+      order_line_id: null,
+      workflow_run_id: null,
+      asset_type: 'still' as const,
+      storage_key: 'path/to/file.png',
+      file_size_bytes: 1024,
+      mime_type: 'image/png',
+      width: 512,
+      height: 512,
+      duration_s: null,
+      render_config: null,
+      is_archived: false,
+      created_at: new Date().toISOString(),
+      download_url: null,
+    }
+    expect(asset.asset_type).toBe('still')
+    expect(asset.cad_file_id).toBeNull()
+  })
+})
+
+describe('cad API', () => {
+  test('generateGltfGeometry is a function', async () => {
+    const { generateGltfGeometry } = await import('../../api/cad')
+    expect(typeof generateGltfGeometry).toBe('function')
+  })
+
+  test('getCadThumbnailUrl returns correct URL', async () => {
+    const { getCadThumbnailUrl } = await import('../../api/cad')
+    const url = getCadThumbnailUrl('test-uuid')
+    expect(url).toBe('/api/cad/test-uuid/thumbnail')
+  })
+})
+
+describe('Scale request validation', () => {
+  test('allowed services', () => {
+    const allowed = ['render-worker', 'worker', 'worker-thumbnail']
+    expect(allowed).toContain('render-worker')
+    expect(allowed).toContain('worker-thumbnail')
+    expect(allowed).not.toContain('postgres')
+  })
+})