refactor(core): standardize and reorder imports across admin services and modules

Optimize the structure and readability of import statements in `admin` services, modules, and controllers. Ensure consistency and logical grouping for improved maintainability.

frontend/src/services/admin.service.ts

@@ -1,4 +1,4 @@
-import { api } from "./api";
+import api from "@/lib/api";
 
 export interface AdminStats {
 	users: number;