feat(home-button): add HomeButton component for hospital/garden navigation

scripts/objects/home_button.gd

@@ -0,0 +1,21 @@
+## HomeButton — tappable button that navigates between the hospital and the garden area.
+class_name HomeButton extends Node2D
+
+const BUTTON_HALF_SIZE: float = 32.0
+
+@export var go_to_garden: bool = true
+
+
+func _input(event: InputEvent) -> void:
+	if not event is InputEventScreenTouch:
+		return
+	if not (event as InputEventScreenTouch).pressed:
+		return
+	var touch_pos: Vector2 = (event as InputEventScreenTouch).position
+	var local: Vector2 = to_local(touch_pos)
+	if abs(local.x) > BUTTON_HALF_SIZE or abs(local.y) > BUTTON_HALF_SIZE:
+		return
+	if go_to_garden:
+		RoomNavigator.go_to_home()
+	else:
+		RoomNavigator.go_to_hospital()