ProtonVPN/proton-vpn-gtk-app ? reverse-engineered prompt

Build me a desktop Linux app for Proton VPN that feels polished and simple to use.

I want a GTK based client where a user can sign in with their Proton account, see their VPN status, connect and disconnect easily, pick a server or region, and access the main features Proton VPN users expect after they are authenticated. Make it handle user settings locally, save logs in the usual app folder, and keep the interface clean and native looking on Linux.

Please set it up so it can be run and developed from the repo, with the needed tests included, and make sure it works well on regular desktop Linux as well as in headless test setups if needed. If you need to check the current library docs or best practices online, go ahead and do that.