feat: introduce new app routes with modular structure and enhanced features

Added modular app routes including `login`, `dashboard`, `categories`, `trends`, and `upload`. Introduced reusable components such as `ContentList`, `ContentSkeleton`, and `AppSidebar` for improved UI consistency. Enhanced authentication with `AuthProvider` and implemented lazy loading, dynamic layouts, and infinite scrolling for better performance.

frontend/src/services/auth.service.ts

@@ -0,0 +1,22 @@
+import api from "@/lib/api";
+import type { LoginResponse } from "@/types/auth";
+
+export const AuthService = {
+  async login(email: string, password: string): Promise<LoginResponse> {
+    const { data } = await api.post<LoginResponse>("/auth/login", { email, password });
+    return data;
+  },
+
+  async register(payload: any): Promise<any> {
+    const { data } = await api.post("/auth/register", payload);
+    return data;
+  },
+
+  async logout(): Promise<void> {
+    await api.post("/auth/logout");
+  },
+
+  async refresh(): Promise<void> {
+    await api.post("/auth/refresh");
+  },
+};