fix: ruff lint + format fixes in tests, ESLint fixes in frontend

backend/app/routers/datev.py

@@ -19,7 +19,9 @@ from app.services import datev_service
 router = APIRouter(prefix="/datev", tags=["datev"])
 
 
-@router.post("/export", response_model=DATEVExportResponse, status_code=status.HTTP_201_CREATED)
+@router.post(
+    "/export", response_model=DATEVExportResponse, status_code=status.HTTP_201_CREATED
+)
 async def create_export(
     body: DATEVExportCreate,
     db: AsyncSession = Depends(get_db),
@@ -37,7 +39,9 @@ async def create_export(
     return DATEVExportResponse.model_validate(export)
 
 
-@router.get("/exports", response_model=DATEVExportListResponse, status_code=status.HTTP_200_OK)
+@router.get(
+    "/exports", response_model=DATEVExportListResponse, status_code=status.HTTP_200_OK
+)
 async def list_exports(
     db: AsyncSession = Depends(get_db),
     pagination: dict = Depends(get_pagination),
@@ -68,7 +72,12 @@ async def download_export(
     if result is None:
         raise HTTPException(
             status_code=status.HTTP_404_NOT_FOUND,
-            detail={"error": {"code": "EXPORT_NOT_FOUND", "message": "DATEV export not found"}},
+            detail={
+                "error": {
+                    "code": "EXPORT_NOT_FOUND",
+                    "message": "DATEV export not found",
+                }
+            },
         )
     filename, csv_bytes = result
     return Response(