feat(main_menu): add exit button and refactor layout with ColumnLayout

- Add `should_close_window()` method to force window close from UI.
- Replace standalone button with ColumnLayout for proper centering.
- Add "Exit" button that calls `should_close_window()`.
- Update ESC key handling to only close window when game is not running.
- Fix ColumnLayout to respect parent's anchor instead of hardcoded TOP_LEFT.
- Remove unused parameter name in Image::update for consistency.

src/ui/column_layout.cpp

@@ -16,7 +16,7 @@ void ColumnLayout::layout() {
     int y = 0;
     for (auto& child : children) {
         child->set_offset({0, y});
-        child->set_anchor(Anchor::TOP_LEFT);
+        child->set_anchor(m_anchor);
         y += child->height() + m_spacing;
     }
 }

src/ui/image.cpp

@@ -5,7 +5,7 @@
 
 namespace Cubed {
 Image::Image(Widget* parent) : Widget(parent) {}
-void Image::update(float dt) { (void)dt; }
+void Image::update(float) {}
 void Image::render(Renderer& renderer) { renderer.render_image(*this); }
 
 Image& Image::set_image(const std::string& path,

src/ui/main_menu_ui_manager.cpp

@@ -5,29 +5,48 @@
 #include "Cubed/scene/main_menu_scene.hpp"
 #include "Cubed/scene/scene_manager.hpp"
 #include "Cubed/ui/button.hpp"
+#include "Cubed/ui/column_layout.hpp"
 namespace Cubed {
 
 MainMenuUIManager::MainMenuUIManager(MainMenuScene& scene) : m_scene(scene) {}
 MainMenuUIManager::~MainMenuUIManager() {}
 
 void MainMenuUIManager::init() {
+    auto& renderer = m_scene.scene_manager().app().renderer();
+    auto layout = std::make_unique<ColumnLayout>(nullptr);
+    layout->set_spacing(20);
+    layout->set_anchor(Anchor::CENTER);
+    layout->set_window_size(renderer.window_width(), renderer.window_height());
+    {
+        auto& start_game_button = layout->add_child<Button>();
 
-    auto start_game_button = std::make_unique<Button>(nullptr);
+        auto& back = start_game_button.set_background<Image>();
+        back.set_image("texture/ui/button001.png",
+                       m_scene.scene_manager().app().texture_manager());
+        auto& fore = start_game_button.set_foreground<Label>();
+        fore.set_text("Start Game");
+        fore.set_scale(0.6f);
+        start_game_button.set_clicked([this]() {
+            m_scene.scene_manager().request_push(SceneType::WORLD);
+        });
+        start_game_button.set_scale(4.0f);
+    }
 
-    auto& back = start_game_button->set_background<Image>();
-    back.set_image("texture/ui/button001.png",
-                   m_scene.scene_manager().app().texture_manager());
-    auto& fore = start_game_button->set_foreground<Label>();
-    fore.set_text("Start Game");
-    fore.set_scale(0.6f);
-    start_game_button->set_window_size(
-        m_scene.scene_manager().app().renderer().window_width(),
-        m_scene.scene_manager().app().renderer().window_height());
-    start_game_button->set_clicked(
-        [this]() { m_scene.scene_manager().request_push(SceneType::WORLD); });
-    start_game_button->set_scale(3.0f);
-    start_game_button->set_anchor(Anchor::CENTER);
-    m_widgets.try_emplace("start game", std::move(start_game_button));
+    auto& exit_game = layout->add_child<Button>();
+
+    {
+        auto& back = exit_game.set_background<Image>();
+        back.set_image("texture/ui/button001.png",
+                       m_scene.scene_manager().app().texture_manager());
+        auto& fore = exit_game.set_foreground<Label>();
+        fore.set_scale(0.6f).set_text("Exit");
+        exit_game.set_scale(4.0f);
+        exit_game.set_clicked([this]() {
+            m_scene.scene_manager().app().window().should_close_window();
+        });
+    }
+
+    m_widgets.try_emplace("main menu layout", std::move(layout));
 }
 
 void MainMenuUIManager::update(float dt) {

src/window.cpp

@@ -73,8 +73,10 @@ bool Window::handle_key_event(const KeyEvent& e) {
         return true;
     }
     if (e.key == Key::ESCAPE && e.action == KeyAction::PRESS) {
-        glfwSetWindowShouldClose(m_window, GLFW_TRUE);
-        return true;
+        if (!m_game_running) {
+            glfwSetWindowShouldClose(m_window, GLFW_TRUE);
+            return true;
+        }
     }
     if (e.key == Key::LEFT_ALT && e.action == KeyAction::PRESS) {
         toggle_mouse_able();
@@ -237,6 +239,9 @@ void Window::set_game_running(bool running) {
     m_mouse_enable = running;
     toggle_mouse_able();
 }
+
+void Window::should_close_window() { glfwSetWindowShouldClose(m_window, true); }
+
 void Window::imgui_init() {
     float dpi_scale_x, dpi_scale_y;
     glfwGetWindowContentScale(m_window, &dpi_scale_x, &dpi_scale_y);