thehasancodes/Expelidos ? reverse-engineered prompt

Build me a simple desktop app in Python that lets me turn an Excel file into JSON.

I want to open a workbook, pick one sheet from it, and convert that sheet into a JSON file I can save anywhere on my computer. The app should be easy to use, with a small window where I can choose the Excel file, see the available sheets, pick one, and then click a button to export it.

Please handle blank rows without breaking, and make sure missing column names are dealt with in a sensible way. Use the usual Python tools for this kind of local app, and keep it lightweight since this is just for quick file conversion on my machine.

If you need to check the latest library docs online, feel free to do that.