• Added a native Linux / Steam Deck SDL2 client with Vulkan rendering, gamepad input and audio.
• Added a desktop disc picker, separate Arcade and Simulation imports, application locking and Linux save-folder locks.
• Added Flatpak build/install/play scripts and a 1280 x 800 initial fullscreen size for the Deck package.
• Added a View + Menu settings shortcut, one pause action per Menu press, disc switching, disc import and Quit game in the overlay.
• I tested installation, disc import and gameplay on a Steam Deck OLED in Desktop Mode. See validation for test coverage.