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/types/auth.ts

@@ -0,0 +1,15 @@
+export interface LoginResponse {
+  message: string;
+  userId: string;
+}
+
+export interface AuthStatus {
+  isAuthenticated: boolean;
+  user: null | {
+    id: string;
+    username: string;
+    displayName?: string;
+    avatarUrl?: string;
+  };
+  isLoading: boolean;
+}

frontend/src/types/content.ts

@@ -0,0 +1,46 @@
+import type { User } from "./user";
+
+export interface Content {
+  id: string;
+  title: string;
+  slug: string;
+  description?: string;
+  url: string;
+  thumbnailUrl?: string;
+  type: "image" | "video";
+  mimeType: string;
+  size: number;
+  width?: number;
+  height?: number;
+  duration?: number;
+  views: number;
+  usageCount: number;
+  favoritesCount: number;
+  tags: (string | Tag)[];
+  category?: Category;
+  authorId: string;
+  author: User;
+  createdAt: string;
+  updatedAt: string;
+}
+
+export interface Tag {
+  id: string;
+  name: string;
+  slug: string;
+}
+
+export interface Category {
+  id: string;
+  name: string;
+  slug: string;
+  description?: string;
+}
+
+
+export interface PaginatedResponse<T> {
+  data: T[];
+  total: number;
+  limit: number;
+  offset: number;
+}

frontend/src/types/user.ts

@@ -0,0 +1,15 @@
+export interface User {
+  id: string;
+  username: string;
+  email: string;
+  displayName?: string;
+  avatarUrl?: string;
+  role: "user" | "admin";
+  createdAt: string;
+}
+
+export interface UserProfile extends User {
+  bio?: string;
+  favoritesCount: number;
+  uploadsCount: number;
+}