neymaristhegoat/obsidian-launcher ? reverse-engineered prompt

Build me a desktop launcher for Minecraft called Obsidian Launcher. It should feel like a polished Electron app with a native C++ core, where users can sign in, manage accounts, create and switch between separate game instances, and launch Minecraft from each one. I want it to store all launcher data in a local app data folder, keep mods, saves, resource packs, shaders, configs, and logs inside each instance, and migrate any old profile files the first time it runs.

Please make it work well on Windows, macOS, and Linux, and include the installer and packaging flow so I can build the right download for the machine I am on. It should also save login tokens securely when the OS supports it, and fall back safely on Linux if there is no keyring. If you need to check current Electron or packaging docs online, go ahead.