hrydgard/PPSSPP ? reverse-engineered prompt

Build me a fast, portable PSP emulator app that works on Android, Windows, Mac, Linux, and iPhone. It should let me load PSP game files without needing a BIOS, show a clean game browser with cover art and basic game info, and make it easy to start playing right away.

I want the controls to work well with both keyboard or controller on desktop and touch controls on mobile, with sensible defaults and the ability to change settings like display, rotation, and save states. If possible, include support for multiplayer and achievements features already mentioned in the project, and make sure the app feels polished, stable, and easy to use.

Please get it building and running from the repo, fix any obvious issues you hit, and look up current docs online if you need to. If there are platform specific quirks, handle them gracefully so the experience is smooth on each device.