Enhance XCUI demo text editing and host bridge

tests/editor/test_editor_console_sink.cpp

@@ -0,0 +1,22 @@
+#include <gtest/gtest.h>
+
+#include "Core/EditorConsoleSink.h"
+
+namespace XCEngine::Debug {
+namespace {
+
+TEST(EditorConsoleSink, GetInstanceTracksRegisteredSinkOnly) {
+    EditorConsoleSink* registeredInstance = nullptr;
+
+    {
+        EditorConsoleSink sink;
+        registeredInstance = &sink;
+
+        EXPECT_EQ(EditorConsoleSink::GetInstance(), registeredInstance);
+    }
+
+    EXPECT_EQ(EditorConsoleSink::GetInstance(), nullptr);
+}
+
+} // namespace
+} // namespace XCEngine::Debug