rework vehicle handling

frontend/src/services/vehicles.ts

@@ -15,6 +15,9 @@ async function unwrap<T>(
   promise: ReturnType<typeof api.get<{ success: boolean; data: T }>>
 ): Promise<T> {
   const response = await promise;
+  if (!response.data?.data) {
+    throw new Error('Invalid API response');
+  }
   return response.data.data;
 }
 
@@ -44,6 +47,9 @@ export const vehiclesApi = {
       '/api/vehicles',
       payload
     );
+    if (!response.data?.data) {
+      throw new Error('Invalid API response');
+    }
     return response.data.data;
   },
 
@@ -52,6 +58,9 @@ export const vehiclesApi = {
       `/api/vehicles/${id}`,
       payload
     );
+    if (!response.data?.data) {
+      throw new Error('Invalid API response');
+    }
     return response.data.data;
   },
 
@@ -74,6 +83,9 @@ export const vehiclesApi = {
       `/api/vehicles/${id}/wartung`,
       payload
     );
+    if (!response.data?.data) {
+      throw new Error('Invalid API response');
+    }
     return response.data.data;
   },
 };