feat: add portable mode support and improve update handling

- Add portable.ini marker file creation in GitHub Actions for portable builds
- Implement is_portable_mode() command to detect portable execution
- Redirect portable users to GitHub releases page for manual updates
- Change update URL to point to latest releases page
- Integrate portable mode detection in Settings UI

src-tauri/src/commands.rs

@@ -674,7 +674,7 @@ pub async fn check_for_updates(handle: tauri::AppHandle) -> Result<bool, String>
     handle
         .opener()
         .open_url(
-            "https://github.com/farion1231/cc-switch/releases",
+            "https://github.com/farion1231/cc-switch/releases/latest",
             None::<String>,
         )
         .map_err(|e| format!("打开更新页面失败: {}", e))?;
@@ -682,6 +682,17 @@ pub async fn check_for_updates(handle: tauri::AppHandle) -> Result<bool, String>
     Ok(true)
 }
 
+/// 判断是否为便携版（绿色版）运行
+#[tauri::command]
+pub async fn is_portable_mode() -> Result<bool, String> {
+    let exe_path = std::env::current_exe().map_err(|e| format!("获取可执行路径失败: {}", e))?;
+    if let Some(dir) = exe_path.parent() {
+        Ok(dir.join("portable.ini").is_file())
+    } else {
+        Ok(false)
+    }
+}
+
 /// VS Code: 获取用户 settings.json 状态
 #[tauri::command]
 pub async fn get_vscode_settings_status() -> Result<ConfigStatus, String> {

src-tauri/src/lib.rs

@@ -377,6 +377,7 @@ pub fn run() {
             commands::get_settings,
             commands::save_settings,
             commands::check_for_updates,
+            commands::is_portable_mode,
             commands::get_vscode_settings_status,
             commands::read_vscode_settings,
             commands::write_vscode_settings,