fix(resourceManager): auto-dismiss file copy notification

复制文件到剪贴板的成功提示改用 withProgress 通知，1.5 秒后自动消失，
无需手动关闭。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Sisyphean-a

src/features/resourceManager/commands.ts

@@ -214,7 +214,13 @@ export class ResourceCommands {
       }
 
       const fileName = path.basename(filePath);
-      vscode.window.showInformationMessage(`文件已复制到剪贴板: ${fileName}`);
+      void vscode.window.withProgress(
+        {
+          location: vscode.ProgressLocation.Notification,
+          title: `文件已复制到剪贴板: ${fileName}`,
+        },
+        () => new Promise<void>((resolve) => setTimeout(resolve, 1500)),
+      );
       Logger.info(`已复制文件到剪贴板: ${filePath}`);
     } catch (error) {
       Logger.error("复制文件到剪贴板失败", error);