rbxpusk/drsim-launcher ? reverse-engineered prompt

Build me a simple desktop launcher for deltarunesim.com that can download the game and make sure every file matches the site’s SHA 256 manifest before it lets the user play.

I want it to feel like a clean little installer and updater, with a basic window, a progress display, and clear messages if something is missing or fails. It should handle first time setup, check for updates, download what it needs, and verify the files after download so users know the game is safe and complete. If the files are already installed and valid, it should open the game right away.

Please make it work as a desktop app with a Rust backend and a simple UI, and include the install scripts for Linux and Windows mentioned in the README. If you need to check anything about current Tauri docs or best practices, look them up online.