Add save actions and cross-platform file manager support (#848)

* files-download-feature

* feat: add save option to file directory context menus and viewer

* fix: open files in the system file manager

packages/vscode/webview/api/files.ts

@@ -115,7 +115,6 @@ export const createVSCodeFilesAPI = (): FilesAPI => ({
 
   async execCommands(commands: string[], cwd: string): Promise<{ success: boolean; results: CommandExecResult[] }> {
     const targetCwd = normalizePath(cwd);
-    // Use extended timeout for command execution (5 minutes)
     const data = await sendBridgeMessageWithOptions<{ success: boolean; results?: CommandExecResult[] }>('api:fs:exec', {
       commands,
       cwd: targetCwd,
@@ -126,4 +125,15 @@ export const createVSCodeFilesAPI = (): FilesAPI => ({
       results: Array.isArray(data?.results) ? data.results : [],
     };
   },
+
+  async downloadFile(path: string): Promise<void> {
+    const target = normalizePath(path);
+    const url = `/api/fs/raw?path=${encodeURIComponent(target)}&download=true`;
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = target.split('/').pop() || 'file';
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+  },
 });