fix(host/linux,clients/android): honor the host/device keyboard layout in keymaps

wlroots injector: the virtual keyboard keymap now defers to the standard
XKB_DEFAULT_RULES/MODEL/LAYOUT/VARIANT/OPTIONS env vars (libxkbcommon
built-ins as fallback) instead of hardcoding evdev/pc105/us, matching the
libei path where the session compositor's own keymap applies. Android:
Keymap gains the same positional-key coverage for non-US layouts (+ tests).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

clients/android/app/src/main/kotlin/io/unom/punktfunk/MainActivity.kt

@@ -72,7 +72,9 @@ class MainActivity : ComponentActivity() {
                         KeyEvent.ACTION_UP -> false
                         else -> return super.dispatchKeyEvent(event)
                     }
-                    val vk = Keymap.toVk(event.keyCode)
+                    // Full-event overload: evdev scancode first (positional under ANY selected
+                    // physical-keyboard layout), keycode fallback — see Keymap docs.
+                    val vk = Keymap.toVk(event)
                     if (vk != 0) {
                         NativeBridge.nativeSendKey(handle, vk, down, 0)
                         return true // consumed — don't let the system also act on it