refactor(home): 将首页改造成opencode服务入口页面

- 移除ChatGPT风格对话界面相关代码
- 添加在首页自动启动/停止opencode serve的IPC调用
- 首页使用webview加载opencode服务器界面

electron/preload.ts

@@ -39,4 +39,6 @@ contextBridge.exposeInMainWorld('electronAPI', {
     ipcRenderer.invoke('remote-upload-file', id, serverHost, port, filePath, remotePath, password),
   remoteDownloadFile: (id: string, serverHost: string, port: number, fileName: string, remotePath: string, localPath: string, password?: string) => 
     ipcRenderer.invoke('remote-download-file', id, serverHost, port, fileName, remotePath, localPath, password),
+  opencodeStartServer: () => ipcRenderer.invoke('opencode-start-server'),
+  opencodeStopServer: () => ipcRenderer.invoke('opencode-stop-server'),
 })