feat(Materials): add new materials navigation and href functions

- Introduced href functions for accessing materials, including hrefMaterials, hrefMaterialSubject, and hrefMaterialDetail.
- Updated AppsScreen to include a new entry for materials, enhancing the app's educational resources section.
- Exported material types in index.ts to support the new materials functionality.

src/types/index.ts

@@ -6,6 +6,7 @@
 // 导出DTO类型作为主要类型
 export * from './dto';
 export * from './schedule';
+export * from './material';
 
 // 兼容旧类型（用于内部组件）
 import type {

src/types/material.ts

@@ -0,0 +1,103 @@
+/**
+ * 学习资料类型定义
+ */
+
+// 文件类型枚举
+export type MaterialFileType = 'pdf' | 'word' | 'ppt';
+
+// 学科分类
+export interface MaterialSubject {
+  id: string;
+  name: string;
+  icon: string; // MaterialCommunityIcons name
+  color: string; // 主题色
+  description?: string;
+  sort_order: number;
+  is_active: boolean;
+  material_count: number;
+  created_at: string;
+  updated_at: string;
+}
+
+// 文件资料
+export interface MaterialFile {
+  id: string;
+  subject_id: string;
+  title: string;
+  description?: string;
+  file_type: MaterialFileType;
+  file_size: number; // 字节数
+  file_url: string;
+  file_name: string;
+  download_count: number;
+  author_id?: string;
+  author_name?: string;
+  tags?: string[];
+  status: 'active' | 'inactive';
+  created_at: string;
+  updated_at: string;
+  subject?: MaterialSubject;
+}
+
+// 学科资料列表响应
+export interface SubjectMaterialsResponse {
+  subject: MaterialSubject;
+  materials: MaterialFile[];
+  total: number;
+  page: number;
+  page_size: number;
+}
+
+// 搜索结果响应
+export interface SearchMaterialsResponse {
+  materials: MaterialFile[];
+  total: number;
+  page: number;
+  page_size: number;
+}
+
+// 文件类型图标映射
+export const MATERIAL_FILE_TYPE_ICONS: Record<MaterialFileType, string> = {
+  pdf: 'file-pdf-box',
+  word: 'file-word-box',
+  ppt: 'file-powerpoint-box',
+};
+
+// 文件类型颜色映射
+export const MATERIAL_FILE_TYPE_COLORS: Record<MaterialFileType, string> = {
+  pdf: '#E53935',
+  word: '#1E88E5',
+  ppt: '#FF9800',
+};
+
+// 文件类型名称映射
+export const MATERIAL_FILE_TYPE_NAMES: Record<MaterialFileType, string> = {
+  pdf: 'PDF',
+  word: 'Word',
+  ppt: 'PPT',
+};
+
+// 文件大小格式化
+export function formatFileSize(bytes: number): string {
+  if (bytes === 0) return '0 B';
+  const k = 1024;
+  const sizes = ['B', 'KB', 'MB', 'GB'];
+  const i = Math.floor(Math.log(bytes) / Math.log(k));
+  return `${parseFloat((bytes / Math.pow(k, i)).toFixed(1))} ${sizes[i]}`;
+}
+
+// 学科颜色预设
+export const SUBJECT_COLORS = [
+  '#FF6B6B', // 红色
+  '#4ECDC4', // 青色
+  '#45B7D1', // 蓝色
+  '#96CEB4', // 绿色
+  '#FFEAA7', // 黄色
+  '#DDA0DD', // 紫色
+  '#F39C12', // 橙色
+  '#3498DB', // 深蓝
+  '#27AE60', // 深绿
+  '#9B59B6', // 深紫
+  '#1ABC9C', // 青绿
+  '#E74C3C', // 深红
+];