natlg/CloudStorageManager ? reverse-engineered prompt

Build me a simple Java web app that lets me manage multiple cloud storage accounts from one place, kind of like seeing cloud drives in a file manager on my computer.

I want to connect Dropbox, Google Drive, and Microsoft OneDrive with OAuth login, then browse folders, upload and download files, rename or delete them, and copy or move items between different cloud accounts. Make it easy to use from a single page interface, with the main view showing the drives and their folders in a clean way.

Please include the setup needed to store app settings like API keys, database connection details, and local temp paths for uploads and downloads. If you need current setup details, look up the latest docs online. Also make sure it runs locally so I can open it in a browser and try it right away.