FlR0X/Discord-Overlay-Hijack-External — reverse-engineered prompt

Build me a small Windows C++ demo that shows a simple ImGui menu through Discord’s current in game overlay on top of another normal app, like Wallpaper Engine or any fullscreen window. I want it to be a proof of concept for learning how desktop overlays work, not a cheat tool or anything that hides from security software.

Keep it simple and easy to run from Visual Studio. The menu can just have a few sample controls, a title, a checkbox, a slider, and a button. Please make the code clean enough that I can understand the main parts, with comments around how it connects to the Discord overlay and how the drawing loop works.

If the Discord overlay behavior has changed, look up current docs or examples online if you need to, and make the project build without me having to guess missing setup steps.