feat(L+M): configurable dashboard widget system + test framework

Phase L: Dashboard widget system
- Migration 046: dashboard_configs table (user/tenant/role fallback cascade)
- DashboardConfig model + dashboard_service with get/upsert per-user and tenant-default
- API router: GET/PUT /api/dashboard/config, GET/PUT /api/dashboard/tenant-default
- Frontend: 5 widget components (ProductionStats, QueueStatus, RecentRenders, CostOverview, WorkerStatus)
- DashboardGrid with API-backed config, DashboardCustomizeModal (checkbox selection, save/cancel)
- Dashboard.tsx: widget grid + analytics section (privileged users)
- Admin.tsx: restructured with new section order and Maintenance 2-col grid

Phase M: Test framework
- Backend: pytest-asyncio + pytest-cov + factory-boy in pyproject.toml
- conftest.py: excel_dir fixtures + async DB fixtures + mock storage/celery stubs
- Domain tests: billing_service, cache_service, notifications_service, imports_sanity
- Integration: test_api_health.py smoke test (requires running backend)
- Frontend: vitest + @testing-library/react + msw added to package.json
- vite.config.ts: test block (jsdom + globals + setupFiles)
- tsconfig.json: exclude src/__tests__ from main tsc (test runner handles its own types)
- MSW handlers for /api/auth/me, Billing.test.tsx, formatters.test.ts

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

backend/tests/conftest.py

@@ -109,3 +109,140 @@ def parsed_linear_schiene(parsed_excel_all):
 @pytest.fixture(scope="session")
 def parsed_anschlagplatten(parsed_excel_all):
     return parsed_excel_all["Anschlagplatten"]
+
+
+# ── Test-DB (nutzt separate Test-Datenbank) ──────────────────────────────────
+
+import os
+import uuid
+import pytest_asyncio
+from typing import AsyncGenerator
+from httpx import AsyncClient, ASGITransport
+from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
+
+TEST_DB_URL = os.environ.get(
+    "TEST_DATABASE_URL",
+    "postgresql+asyncpg://schaeffler:schaeffler@localhost:5432/schaeffler_test"
+)
+
+
+@pytest_asyncio.fixture
+async def test_engine():
+    from app.database import Base
+    from sqlalchemy import text
+    import app.models  # noqa - register all models
+    engine = create_async_engine(TEST_DB_URL, echo=False)
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+    yield engine
+    # Use CASCADE to handle circular FK dependencies in drop
+    async with engine.begin() as conn:
+        await conn.execute(text("DROP SCHEMA public CASCADE"))
+        await conn.execute(text("CREATE SCHEMA public"))
+    await engine.dispose()
+
+
+@pytest_asyncio.fixture
+async def db(test_engine) -> AsyncGenerator[AsyncSession, None]:
+    session_factory = async_sessionmaker(test_engine, expire_on_commit=False)
+    async with session_factory() as session:
+        yield session
+        await session.rollback()
+
+
+# ── Mock-Storage (LocalStorage in tmpdir) ───────────────────────────────────
+
+@pytest.fixture
+def mock_storage(tmp_path, monkeypatch):
+    """Ersetzt MinIO-Storage durch lokalen tmpdir."""
+    import app.core.storage as storage_module
+    from unittest.mock import MagicMock
+    mock = MagicMock()
+    mock.exists.return_value = False
+    mock.upload.return_value = "test/key"
+    mock.download_bytes.return_value = b"fake-stl-data"
+    mock.get_presigned_url.return_value = "http://localhost/presigned"
+    monkeypatch.setattr(storage_module, "_storage_instance", mock)
+    return mock
+
+
+# ── FastAPI Test-Client ──────────────────────────────────────────────────────
+
+@pytest_asyncio.fixture
+async def client(db) -> AsyncGenerator[AsyncClient, None]:
+    """HTTP-Client mit überschriebener DB-Dependency."""
+    from app.main import app
+    from app.database import get_db
+
+    async def override_get_db():
+        yield db
+
+    app.dependency_overrides[get_db] = override_get_db
+    async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as ac:
+        yield ac
+    app.dependency_overrides.clear()
+
+
+# ── Test-User + Auth-Token ───────────────────────────────────────────────────
+
+@pytest_asyncio.fixture
+async def admin_user(db):
+    from app.domains.auth.models import User, UserRole
+    from app.utils.auth import hash_password
+    user = User(
+        id=uuid.uuid4(),
+        email=f"test-admin-{uuid.uuid4().hex[:8]}@test.com",
+        password_hash=hash_password("TestPass123!"),
+        full_name="Test Admin",
+        role=UserRole.admin,
+        is_active=True,
+    )
+    db.add(user)
+    await db.commit()
+    await db.refresh(user)
+    return user
+
+
+@pytest.fixture
+def admin_token(admin_user):
+    from app.utils.auth import create_access_token
+    return create_access_token(str(admin_user.id), admin_user.role.value)
+
+
+@pytest.fixture
+def auth_headers(admin_token):
+    return {"Authorization": f"Bearer {admin_token}"}
+
+
+# ── Celery-Mock ──────────────────────────────────────────────────────────────
+
+@pytest.fixture(autouse=True)
+def mock_celery_tasks(monkeypatch):
+    """Verhindert echte Celery-Task-Dispatching in Tests."""
+    from unittest.mock import MagicMock
+    mock_result = MagicMock()
+    mock_result.id = "test-task-" + str(uuid.uuid4())[:8]
+
+    def mock_delay(*args, **kwargs):
+        return mock_result
+
+    task_paths = [
+        "app.domains.materials.tasks.refresh_asset_library_catalog",
+        "app.tasks.step_tasks.process_step_file",
+        "app.tasks.step_tasks.render_step_thumbnail",
+        "app.tasks.step_tasks.generate_stl_cache",
+        "app.domains.imports.tasks.validate_excel_import",
+        "app.domains.rendering.tasks.render_still_task",
+        "app.domains.rendering.tasks.render_turntable_task",
+    ]
+    for path in task_paths:
+        try:
+            parts = path.rsplit(".", 1)
+            module_path, attr = parts
+            import importlib
+            module = importlib.import_module(module_path)
+            task = getattr(module, attr, None)
+            if task and hasattr(task, "delay"):
+                monkeypatch.setattr(task, "delay", mock_delay)
+        except Exception:
+            pass