danielchalmers/DesktopClock ? reverse-engineered prompt

Build me a Windows desktop clock widget app that stays on top of the desktop and can show a normal digital clock, a countdown to a date, or another time zone.

I want it to feel simple and polished, with a settings window where I can change the date and time format and see a live preview, pick from a few theme presets, change fonts, colors, opacity, and use a background image if I want. It should also support an optional sound when a countdown finishes, a chime on an interval, and a startup option so it opens when Windows starts.

Make it work nicely as a lightweight desktop widget, with a system tray icon and basic controls there too. If there are any Windows specific details you need, look up the current docs online and keep it compatible with modern Windows.