vczh-libraries/iGac ? reverse-engineered prompt

Build me the macOS native version of GacUI in this repo so it can compile and run on a Mac with the included test apps.

I want the project to build cleanly from the command line, with the sample Hello World app, the full control test app, and the remote renderer test all working if possible. Make sure the macOS windowing, input, clipboard, dialogs, and CoreGraphics drawing pieces are wired up so the UI looks and behaves like a real native app. If anything needs current setup details from Apple or Homebrew, look up the latest docs online and use whatever is needed to get it working.

Please keep it aligned with the existing code and build scripts here, and make sure the included tests can be launched without extra manual steps beyond the documented setup.