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

Start by locating the macOS file sync remote file picker entry point and reading how the existing local file picker exposes folder creation. Trace the remote picker flow and any related tests; done means users can create a new folder from the remote file picker dialog and then select it.

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