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/app/domains/admin/dashboard_service.py

@@ -0,0 +1,148 @@
+"""Dashboard widget configuration service.
+
+Provides async functions for loading and persisting per-user and
+tenant-default dashboard widget layouts.
+"""
+import logging
+import uuid
+from datetime import datetime
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.domains.admin.models import DashboardConfig
+
+logger = logging.getLogger(__name__)
+
+# ---------------------------------------------------------------------------
+# Widget type literals
+# ---------------------------------------------------------------------------
+
+WIDGET_TYPES = (
+    "ProductionStats",
+    "QueueStatus",
+    "RecentRenders",
+    "CostOverview",
+    "WorkerStatus",
+)
+
+# Default layouts per role
+_DEFAULT_ADMIN_WIDGETS: list[dict] = [
+    {"widget_type": "ProductionStats", "position": {"col": 0, "row": 0, "w": 1, "h": 1}},
+    {"widget_type": "QueueStatus",     "position": {"col": 1, "row": 0, "w": 1, "h": 1}},
+    {"widget_type": "WorkerStatus",    "position": {"col": 2, "row": 0, "w": 1, "h": 1}},
+    {"widget_type": "RecentRenders",   "position": {"col": 0, "row": 1, "w": 2, "h": 1}},
+    {"widget_type": "CostOverview",    "position": {"col": 2, "row": 1, "w": 1, "h": 1}},
+]
+
+_DEFAULT_CLIENT_WIDGETS: list[dict] = [
+    {"widget_type": "RecentRenders",   "position": {"col": 0, "row": 0, "w": 2, "h": 1}},
+    {"widget_type": "ProductionStats", "position": {"col": 2, "row": 0, "w": 1, "h": 1}},
+]
+
+
+def get_default_widgets_for_role(role: str) -> list[dict]:
+    """Return systemwide default widget layout for a given role.
+
+    admin / project_manager: all 5 widget types.
+    client: RecentRenders + ProductionStats only.
+    """
+    if role in ("admin", "project_manager"):
+        return [w.copy() for w in _DEFAULT_ADMIN_WIDGETS]
+    return [w.copy() for w in _DEFAULT_CLIENT_WIDGETS]
+
+
+async def get_user_dashboard_config(
+    db: AsyncSession,
+    user_id: uuid.UUID,
+    tenant_id: uuid.UUID | None,
+    role: str,
+) -> list[dict]:
+    """Load widget config with fallback cascade.
+
+    1. User-specific config (user_id match).
+    2. Tenant-default config (is_tenant_default=True for the tenant).
+    3. System default based on role.
+    """
+    # 1. User-specific
+    result = await db.execute(
+        select(DashboardConfig).where(DashboardConfig.user_id == user_id)
+    )
+    config = result.scalar_one_or_none()
+    if config is not None:
+        return list(config.widgets) if config.widgets else []
+
+    # 2. Tenant default
+    if tenant_id is not None:
+        result = await db.execute(
+            select(DashboardConfig).where(
+                DashboardConfig.tenant_id == tenant_id,
+                DashboardConfig.is_tenant_default.is_(True),
+            )
+        )
+        tenant_config = result.scalar_one_or_none()
+        if tenant_config is not None:
+            return list(tenant_config.widgets) if tenant_config.widgets else []
+
+    # 3. System default
+    return get_default_widgets_for_role(role)
+
+
+async def upsert_user_dashboard_config(
+    db: AsyncSession,
+    user_id: uuid.UUID,
+    tenant_id: uuid.UUID | None,
+    widgets: list[dict],
+) -> DashboardConfig:
+    """Save or update the user-specific widget config."""
+    result = await db.execute(
+        select(DashboardConfig).where(DashboardConfig.user_id == user_id)
+    )
+    config = result.scalar_one_or_none()
+
+    if config is None:
+        config = DashboardConfig(
+            user_id=user_id,
+            tenant_id=tenant_id,
+            widgets=widgets,
+            is_tenant_default=False,
+        )
+        db.add(config)
+    else:
+        config.widgets = widgets
+        config.updated_at = datetime.utcnow()
+
+    await db.commit()
+    await db.refresh(config)
+    return config
+
+
+async def upsert_tenant_default(
+    db: AsyncSession,
+    tenant_id: uuid.UUID,
+    widgets: list[dict],
+) -> DashboardConfig:
+    """Set the tenant-default widget config (admin only)."""
+    result = await db.execute(
+        select(DashboardConfig).where(
+            DashboardConfig.tenant_id == tenant_id,
+            DashboardConfig.is_tenant_default.is_(True),
+        )
+    )
+    config = result.scalar_one_or_none()
+
+    if config is None:
+        config = DashboardConfig(
+            tenant_id=tenant_id,
+            user_id=None,
+            widgets=widgets,
+            is_tenant_default=True,
+        )
+        db.add(config)
+    else:
+        config.widgets = widgets
+        config.updated_at = datetime.utcnow()
+
+    await db.commit()
+    await db.refresh(config)
+    return config