ui: add main menu scene and interactive button widget

- Implement MainMenuScene with a "Start Game" button that pushes the WorldScene.
- Extend Button class with background/foreground, hover detection, and size queries.
- Add virtual width/height and event handlers to Widget base class.
- Update WorldUIManager to propagate mouse move events.
- Adjust Window mouse mode based on game running state.

src/ui/main_menu_ui_manager.cpp

@@ -0,0 +1,133 @@
+#include "Cubed/ui/main_menu_ui_manager.hpp"
+
+#include "Cubed/app.hpp"
+#include "Cubed/render/renderer.hpp"
+#include "Cubed/scene/main_menu_scene.hpp"
+#include "Cubed/scene/scene_manager.hpp"
+#include "Cubed/ui/button.hpp"
+namespace Cubed {
+
+MainMenuUIManager::MainMenuUIManager(MainMenuScene& scene) : m_scene(scene) {}
+MainMenuUIManager::~MainMenuUIManager() {}
+
+void MainMenuUIManager::init() {
+
+    auto start_game_button = std::make_unique<Button>();
+    auto& back = start_game_button->set_background<Image>();
+    back.set_image("texture/ui/button001.png",
+                   m_scene.scene_manager().app().texture_manager());
+    back.set_scale(3.0f);
+    auto& fore = start_game_button->set_foreground<Label>();
+    fore.set_text("Start Game");
+
+    start_game_button->set_clicked(
+        [this]() { m_scene.scene_manager().request_push(SceneType::WORLD); });
+    start_game_button->set_position(
+        m_scene.scene_manager().app().renderer().window_width() / 2.0f +
+            back.width() / 2.0f,
+        m_scene.scene_manager().app().renderer().window_width() / 2.0f +
+            back.height() / 2.0f);
+
+    m_widgets.try_emplace("start game", std::move(start_game_button));
+}
+void MainMenuUIManager::update(float dt) {
+    for (auto& w : m_widgets) {
+        w.second->update(dt);
+    }
+}
+void MainMenuUIManager::render(Renderer& renderer) {
+    renderer.begin_render_ui();
+
+    for (auto& widget : m_widgets) {
+        widget.second->render(renderer);
+    }
+
+    renderer.end_render_ui();
+}
+bool MainMenuUIManager::handle_event(const Event& e) {
+    return std::visit(
+        Overloaded{[this](const MouseMoveEvent& e) {
+                       if (handle_mouse_move_event(e)) {
+                           return true;
+                       }
+                       return false;
+                   },
+                   [this](const MouseButtonEvent& e) {
+                       if (handle_mouse_button_event(e)) {
+                           return true;
+                       }
+                       return false;
+                   },
+                   [this](const MouseWheelEvent& e) {
+                       if (handle_mouse_wheel_event(e)) {
+                           return true;
+                       }
+                       return false;
+                   },
+                   [this](const KeyEvent& e) {
+                       if (handle_key_event(e)) {
+                           return true;
+                       }
+                       return false;
+                   },
+                   [](const TextInputEvent&) { return false; },
+                   [this](const WindowResizeEvent& e) {
+                       handle_window_resize_event(e);
+                       return false;
+                   },
+                   [](const FrameBufferResizeEvent&) { return false; }
+
+        },
+        e);
+}
+bool MainMenuUIManager::handle_mouse_move_event(const MouseMoveEvent& e) {
+    for (auto& w : m_widgets) {
+        if (w.second->handle_mouse_move_event(e)) {
+            return true;
+        }
+    }
+    return false;
+}
+bool MainMenuUIManager::handle_mouse_button_event(const MouseButtonEvent& e) {
+    for (auto& w : m_widgets) {
+        if (w.second->handle_mouse_button_event(e)) {
+            return true;
+        }
+    }
+    return false;
+}
+bool MainMenuUIManager::handle_window_resize_event(const WindowResizeEvent& e) {
+    auto it = m_widgets.find("start game");
+    if (it != m_widgets.end()) {
+        auto* start_game = dynamic_cast<Button*>(it->second.get());
+        if (start_game) {
+            start_game->set_position(e.width / 2 + start_game->width() / 2,
+                                     e.height / 2 + start_game->height() / 2);
+        }
+    }
+    for (auto& w : m_widgets) {
+        if (w.second->handle_window_resize_event(e)) {
+            return true;
+        }
+    }
+    return false;
+}
+bool MainMenuUIManager::handle_mouse_wheel_event(const MouseWheelEvent& e) {
+    for (auto& w : m_widgets) {
+        if (w.second->handle_mouse_wheel_event(e)) {
+            return true;
+        }
+    }
+    return false;
+}
+bool MainMenuUIManager::handle_key_event(const KeyEvent& e) {
+    for (auto& w : m_widgets) {
+        if (w.second->handle_key_event(e)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+} // namespace Cubed