chore(client): add gdUnit4 test framework addon

Vendor gdUnit4 for Godot 4 client testing (D-030).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/addons/gdUnit4/src/ui/menu/GdUnitScriptEditorContextMenuHandler.gd

@@ -0,0 +1,41 @@
+@tool
+extends EditorContextMenuPlugin
+
+
+var _context_menus: Array[GdUnitContextMenuItem] = []
+
+
+func _init() -> void:
+	var is_test_suite := func is_visible(script: Script, is_ts: bool) -> bool:
+		return GdUnitTestSuiteScanner.is_test_suite(script) == is_ts
+	_context_menus.append(GdUnitContextMenuItem.new(
+		GdUnitCommandScriptEditorRunTests.ID,
+		"Run Tests",
+		is_test_suite.bind(true)
+	))
+	_context_menus.append(GdUnitContextMenuItem.new(
+		GdUnitCommandScriptEditorDebugTests.ID,
+		"Debug Tests",
+		is_test_suite.bind(true)
+	))
+	_context_menus.append(GdUnitContextMenuItem.new(
+		GdUnitCommandScriptEditorCreateTest.ID,
+		"Create Test",
+		is_test_suite.bind(false)
+	))
+
+	# setup shortcuts
+	for menu_item in _context_menus:
+		if menu_item.shortcut():
+			add_menu_shortcut(menu_item.shortcut(), menu_item.execute.unbind(1))
+
+
+func _popup_menu(_paths: PackedStringArray) -> void:
+	var current_script := EditorInterface.get_script_editor().get_current_script()
+
+	for menu_item in _context_menus:
+		if menu_item.is_visible(current_script):
+			if menu_item.shortcut():
+				add_context_menu_item_from_shortcut(menu_item.name, menu_item.shortcut())
+			else:
+				add_context_menu_item(menu_item.name, menu_item.execute.unbind(1))