实现跨边界拖拽功能：支持从浏览器拖拽文件到系统

主要改进：
- 使用 File System Access API 实现真正的跨应用边界文件传输
- 支持拖拽到窗口外自动触发系统保存对话框
- 智能路径记忆功能，记住用户上次选择的保存位置
- 多文件自动打包为 ZIP 格式
- 现代浏览器优先使用新 API，旧浏览器降级到传统下载
- 完整的视觉反馈和进度显示

技术实现：
- 新增 useDragToSystemDesktop hook 处理系统级拖拽
- 扩展 Electron 主进程支持拖拽临时文件管理
- 集成 JSZip 库支持多文件打包
- 使用 IndexedDB 存储用户偏好的保存路径
- 优化文件管理器拖拽事件处理链

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/types/electron.d.ts

@@ -0,0 +1,66 @@
+export interface ElectronAPI {
+  getAppVersion: () => Promise<string>;
+  getPlatform: () => Promise<string>;
+
+  getServerConfig: () => Promise<any>;
+  saveServerConfig: (config: any) => Promise<any>;
+  testServerConnection: (serverUrl: string) => Promise<any>;
+
+  showSaveDialog: (options: any) => Promise<any>;
+  showOpenDialog: (options: any) => Promise<any>;
+
+  onUpdateAvailable: (callback: Function) => void;
+  onUpdateDownloaded: (callback: Function) => void;
+
+  removeAllListeners: (channel: string) => void;
+  isElectron: boolean;
+  isDev: boolean;
+
+  invoke: (channel: string, ...args: any[]) => Promise<any>;
+
+  // 拖拽API
+  createTempFile: (fileData: {
+    fileName: string;
+    content: string;
+    encoding?: 'base64' | 'utf8';
+  }) => Promise<{
+    success: boolean;
+    tempId?: string;
+    path?: string;
+    error?: string;
+  }>;
+
+  createTempFolder: (folderData: {
+    folderName: string;
+    files: Array<{
+      relativePath: string;
+      content: string;
+      encoding?: 'base64' | 'utf8';
+    }>;
+  }) => Promise<{
+    success: boolean;
+    tempId?: string;
+    path?: string;
+    error?: string;
+  }>;
+
+  startDragToDesktop: (dragData: {
+    tempId: string;
+    fileName: string;
+  }) => Promise<{
+    success: boolean;
+    error?: string;
+  }>;
+
+  cleanupTempFile: (tempId: string) => Promise<{
+    success: boolean;
+    error?: string;
+  }>;
+}
+
+declare global {
+  interface Window {
+    electronAPI: ElectronAPI;
+    IS_ELECTRON: boolean;
+  }
+}