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_router.py

@@ -0,0 +1,152 @@
+"""Dashboard widget configuration endpoints."""
+import logging
+import uuid
+from typing import Any
+
+from fastapi import APIRouter, Depends
+from pydantic import BaseModel
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.domains.admin.dashboard_service import (
+    get_user_dashboard_config,
+    upsert_user_dashboard_config,
+    upsert_tenant_default,
+)
+from app.utils.auth import get_current_user, require_admin
+from app.models.user import User
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(prefix="/dashboard", tags=["dashboard"])
+
+
+# ---------------------------------------------------------------------------
+# Schemas
+# ---------------------------------------------------------------------------
+
+class WidgetPosition(BaseModel):
+    col: int
+    row: int
+    w: int
+    h: int
+
+
+class WidgetConfig(BaseModel):
+    widget_type: str
+    position: WidgetPosition
+    config: dict[str, Any] | None = None
+
+
+class DashboardConfigPayload(BaseModel):
+    widgets: list[WidgetConfig]
+
+
+class DashboardConfigResponse(BaseModel):
+    widgets: list[WidgetConfig]
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+def _to_response(widgets: list[dict]) -> DashboardConfigResponse:
+    parsed = []
+    for w in widgets:
+        pos = w.get("position", {})
+        parsed.append(
+            WidgetConfig(
+                widget_type=w.get("widget_type", ""),
+                position=WidgetPosition(
+                    col=pos.get("col", 0),
+                    row=pos.get("row", 0),
+                    w=pos.get("w", 1),
+                    h=pos.get("h", 1),
+                ),
+                config=w.get("config"),
+            )
+        )
+    return DashboardConfigResponse(widgets=parsed)
+
+
+# ---------------------------------------------------------------------------
+# Endpoints
+# ---------------------------------------------------------------------------
+
+@router.get("/config", response_model=DashboardConfigResponse)
+async def get_config(
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+) -> DashboardConfigResponse:
+    """Load the current user's dashboard widget config (with fallback cascade)."""
+    widgets = await get_user_dashboard_config(
+        db=db,
+        user_id=current_user.id,
+        tenant_id=current_user.tenant_id,
+        role=current_user.role.value,
+    )
+    return _to_response(widgets)
+
+
+@router.put("/config", response_model=DashboardConfigResponse)
+async def update_config(
+    payload: DashboardConfigPayload,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+) -> DashboardConfigResponse:
+    """Save or update the current user's dashboard widget config."""
+    widgets_raw = [w.model_dump() for w in payload.widgets]
+    config = await upsert_user_dashboard_config(
+        db=db,
+        user_id=current_user.id,
+        tenant_id=current_user.tenant_id,
+        widgets=widgets_raw,
+    )
+    return _to_response(list(config.widgets))
+
+
+@router.get("/tenant-default", response_model=DashboardConfigResponse)
+async def get_tenant_default(
+    current_user: User = Depends(require_admin),
+    db: AsyncSession = Depends(get_db),
+) -> DashboardConfigResponse:
+    """Load the tenant-default dashboard widget config (admin only)."""
+    from sqlalchemy import select
+    from app.domains.admin.models import DashboardConfig
+
+    if current_user.tenant_id is None:
+        return DashboardConfigResponse(widgets=[])
+
+    result = await db.execute(
+        select(DashboardConfig).where(
+            DashboardConfig.tenant_id == current_user.tenant_id,
+            DashboardConfig.is_tenant_default.is_(True),
+        )
+    )
+    config = result.scalar_one_or_none()
+    if config is None:
+        return DashboardConfigResponse(widgets=[])
+    return _to_response(list(config.widgets))
+
+
+@router.put("/tenant-default", response_model=DashboardConfigResponse)
+async def update_tenant_default(
+    payload: DashboardConfigPayload,
+    current_user: User = Depends(require_admin),
+    db: AsyncSession = Depends(get_db),
+) -> DashboardConfigResponse:
+    """Set the tenant-default widget config (admin only)."""
+    if current_user.tenant_id is None:
+        from fastapi import HTTPException, status
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Admin user has no tenant_id assigned.",
+        )
+
+    widgets_raw = [w.model_dump() for w in payload.widgets]
+    config = await upsert_tenant_default(
+        db=db,
+        tenant_id=current_user.tenant_id,
+        widgets=widgets_raw,
+    )
+    return _to_response(list(config.widgets))