fix: 修复聊天系统编译错误

- 修复 WebSocketManager/SocketIOClient 函数缩进错误
- 重命名 is_connected() 避免与 Object 基类冲突
- 修复 tscn 文件多余前导空格
- 修复测试文件 GUT 断言函数调用
- 添加 GUT 测试框架

addons/gut/gui/ShellOutOptions.tscn

@@ -0,0 +1,34 @@
+[gd_scene load_steps=2 format=3 uid="uid://ckv5eh8xyrwbk"]
+
+[ext_resource type="Script" uid="uid://c64u22kybimgi" path="res://addons/gut/gui/ShellOutOptions.gd" id="1_ht2pf"]
+
+[node name="ShellOutOptions" type="ConfirmationDialog"]
+oversampling_override = 1.0
+title = "GUT Run Mode (Experimental)"
+position = Vector2i(0, 36)
+size = Vector2i(516, 557)
+visible = true
+script = ExtResource("1_ht2pf")
+
+[node name="ScrollContainer" type="ScrollContainer" parent="."]
+custom_minimum_size = Vector2(500, 500)
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+offset_left = 8.0
+offset_top = 8.0
+offset_right = -8.0
+offset_bottom = -49.0
+grow_horizontal = 2
+grow_vertical = 2
+
+[node name="VBoxContainer" type="VBoxContainer" parent="ScrollContainer"]
+layout_mode = 2
+size_flags_horizontal = 3
+size_flags_vertical = 3
+
+[node name="AcceptDialog" type="AcceptDialog" parent="."]
+oversampling_override = 1.0
+size = Vector2i(399, 106)
+dialog_text = "Invalid arguments.  The following cannot be used:
+-d --debug -s --script"