refactor(contents): reorder imports and improve code formatting

Standardize import order in `contents.controller.ts` and related files for better code readability. Adjust SQL formatting in repository methods for consistency.

frontend/src/components/content-card.tsx

@@ -16,6 +16,7 @@ import {
 	CardHeader,
 } from "@/components/ui/card";
 import { useAuth } from "@/providers/auth-provider";
+import { ContentService } from "@/services/content.service";
 import { FavoriteService } from "@/services/favorite.service";
 import type { Content } from "@/types/content";