Add "New Folder" button to file sync remote file picker

## Feature Request

Add a "New Folder" button to the remote file picker to allow users to create new folders directly within the remote file system dialog.

## Current Behavior
Users must create folders outside of the remote file picker before they can select them.

## Desired Behavior
Users should be able to create new folders directly within the remote file picker dialog.

## Workaround
Currently, users can pick a folder using the remote file picker and append the desired folder name to the string in the text field to create the folder structure.

## Benefits
- Improved user experience
- Streamlined workflow for remote file management
- Consistency with local file picker functionality

首先找到远程文件选择器的实现，并将其与本地文件选择器进行比较，因为 issue 提到了二者之间的一致性。确认远程文件夹的创建是如何处理的，然后添加按钮，使用户能够在对话框中创建并选择文件夹；完成标准是远程选择器支持这一工作流，而无需使用文本字段 workaround。

由索引模型根据 Issue 内容生成。