add tween plugin and refactoring UI

addons/TweenFX/TweenManager.gd

@@ -0,0 +1,43 @@
+## Internal tracking system for TweenFX.
+## [br][br]
+## Manages active tweens per node, handles cleanup when nodes are freed,
+## and provides stop/query methods. Not intended for direct use — 
+## access through [TweenFX] instead.
+
+static var _active: Dictionary = {}  # { node: { TweenFX.Animations.X: tween } }
+
+static func track(node: CanvasItem, anim: TweenFX.Animations, tween: Tween) -> void:
+	if not _active.has(node):
+		_active[node] = {}
+		if not node.tree_exiting.is_connected(_on_node_exiting):
+			node.tree_exiting.connect(_on_node_exiting.bind(node), CONNECT_ONE_SHOT)
+	_active[node][anim] = tween
+	tween.finished.connect(_on_tween_finished.bind(node, anim), CONNECT_ONE_SHOT)
+
+static func stop(node: CanvasItem, anim: TweenFX.Animations) -> void:
+	if not _active.has(node) or not _active[node].has(anim):
+		return
+	_active[node][anim].kill()
+	_active[node].erase(anim)
+	if _active[node].is_empty():
+		_active.erase(node)
+
+static func stop_all(node: CanvasItem) -> void:
+	if not _active.has(node):
+		return
+	for tween in _active[node].values():
+		tween.kill()
+	_active.erase(node)
+
+static func is_playing(node: CanvasItem, anim: TweenFX.Animations) -> bool:
+	return _active.has(node) and _active[node].has(anim)
+
+static func _on_tween_finished(node: CanvasItem, anim: TweenFX.Animations) -> void:
+	if not _active.has(node):
+		return
+	_active[node].erase(anim)
+	if _active[node].is_empty():
+		_active.erase(node)
+
+static func _on_node_exiting(node: CanvasItem) -> void:
+	_active.erase(node)