imputnet/helium-macos ? reverse-engineered prompt

Build me a clean macOS build and packaging setup for Helium Browser so I can compile it, test it locally, and make a signed app release without a lot of manual steps.

I want the project to be easy to set up on a Mac, with simple scripts for downloading whatever resources are needed, building the browser, and packaging it into a proper app. Please make it work well for day to day development too, so I can quickly rebuild after changes and iterate on the browser features. If anything depends on current upstream Chromium or macOS build details, look up the latest docs online if you need to.

Keep it focused on the macOS app experience, including the bits needed for permissions, signing, and release packaging. If there are obvious missing instructions or setup steps, add them in a way that a normal developer could follow without digging through a lot of files.