fix: unsubscribe VisibilityChanged in _ExitTree, use IsActionReleased for ui_cancel, expose ApplyGamepadDeadzone public

scripts/UI/GameplaySettings.cs

@@ -73,11 +73,7 @@ public partial class GameplaySettings : Control
     private void OnDeadzoneChanged(double value)
     {
         SettingsManager.Instance.GamepadDeadzone = (float)value;
-        foreach (var action in new[] { "left", "right", "up", "down" })
-        {
-            if (InputMap.HasAction(action))
-                InputMap.ActionSetDeadzone(action, (float)value);
-        }
+        SettingsManager.Instance.ApplyGamepadDeadzone();
         DeadzoneValueLabel.Text = $"{value:F2}";
         SaveSettings();
     }