Added gameplay_input manager.

Refactored menus, player, and escape_capsule to utilize new system.
Actions defined in Godot project file with default bindings.
Player/Vehicles now react to actions and GameplayInput states instead of polling Input directly.
They respond to commands via `_handle_gameplay_command` and should not implement _unhandled_input directly.
Kept some debugging input handling code in `player.gd` for things like F3/F5/F4/PageUp/PageDown.
We may want to move much of this out of `player.gd` into something that handles the gamestate more generally.

Scenes/Scripts/character_creation.gd

@@ -64,6 +64,7 @@ var culture_buttons: Array[Button] = []
 
 func _ready() -> void:
 	Input.mouse_mode = Input.MOUSE_MODE_VISIBLE
+	GameplayInput.set_menu_open(self, true)
 	name_input = _find("NameInput") as LineEdit
 	background_list = _find("BackgroundL") as Control
 	if background_list == null:
@@ -126,6 +127,20 @@ func _ready() -> void:
 	if backgrounds.size() > 0:
 		_select_background(backgrounds[0])
 	_set_sex("male")
+	if sex_male:
+		sex_male.grab_focus()
+
+
+## Controller cancel follows the existing back command without changing creation data.
+func _unhandled_input(event: InputEvent) -> void:
+	if event.is_action_pressed("ui_cancel"):
+		get_viewport().set_input_as_handled()
+		_on_back()
+
+
+## Releases menu ownership when entering gameplay or returning to the main menu.
+func _exit_tree() -> void:
+	GameplayInput.set_menu_open(self, false)
 
 
 func _find(n: String) -> Node: