Replaces the hard-coded OpenXR menu long-press shutdown with a
proper rebindable hotkey (HK_ANDROID_RETURN_TO_MAIN_MENU, HKGP_ANDROID
group), defaulting to a 3-second hold of the left controller's Menu
button. The hold threshold lives in HotkeyDispatcher to keep the input
side authoritative.
The Android settings UI now hides hotkey groups and individual controls
that have no dispatcher wiring, so users can't bind actions that would
silently no-op at runtime. Adds a Control.getName() JNI getter for
identifying functional controls by their untranslated C++ name.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
