SDL3-backed gamepad manager polls at 60Hz, handles hotplug,
exposes battery/rumble/LED per device. Game launcher aggregates
XDG desktop entries, Steam appmanifests, and Flatpak into a
single sorted model.
Game Center uses the new model instead of folio's search model.
D-pad/A/B/Y navigate and launch. Guide button toggles the
overlay. Battery and controller status shown in the HUD.
