refactor: Update GUI components and integrate new palette widget

- Removed references to the old `EnhancedPaletteEditor` and replaced it with the new `PaletteWidget` across various files, including canvas and context menu implementations.
- Updated CMake configurations to include the new `palette_widget` source files, ensuring proper integration into the build system.
- Refactored GUI code to enhance modularity and maintainability, improving the overall user experience in palette management and editing functionalities.
- Introduced new UI components for background rendering and editor selection dialogs, enhancing the application's graphical interface.

src/app/editor/ui/welcome_screen.h

@@ -0,0 +1,111 @@
+#ifndef YAZE_APP_EDITOR_UI_WELCOME_SCREEN_H_
+#define YAZE_APP_EDITOR_UI_WELCOME_SCREEN_H_
+
+#include <functional>
+#include <string>
+#include <vector>
+
+namespace yaze {
+namespace editor {
+
+/**
+ * @struct RecentProject
+ * @brief Information about a recently used project
+ */
+struct RecentProject {
+  std::string name;
+  std::string filepath;
+  std::string rom_title;
+  std::string last_modified;
+  std::string thumbnail_path;  // Optional screenshot
+  int days_ago = 0;
+};
+
+/**
+ * @class WelcomeScreen
+ * @brief Modern welcome screen with project grid and quick actions
+ */
+class WelcomeScreen {
+ public:
+  WelcomeScreen();
+  
+  /**
+   * @brief Show the welcome screen
+   * @param p_open Pointer to open state
+   * @return True if an action was taken (ROM opened, etc.)
+   */
+  bool Show(bool* p_open);
+  
+  /**
+   * @brief Set callback for opening ROM
+   */
+  void SetOpenRomCallback(std::function<void()> callback) {
+    open_rom_callback_ = callback;
+  }
+  
+  /**
+   * @brief Set callback for creating new project
+   */
+  void SetNewProjectCallback(std::function<void()> callback) {
+    new_project_callback_ = callback;
+  }
+  
+  /**
+   * @brief Set callback for opening project
+   */
+  void SetOpenProjectCallback(std::function<void(const std::string&)> callback) {
+    open_project_callback_ = callback;
+  }
+  
+  /**
+   * @brief Refresh recent projects list from the project manager
+   */
+  void RefreshRecentProjects();
+  
+  /**
+   * @brief Update animation time for dynamic effects
+   */
+  void UpdateAnimations();
+  
+  /**
+   * @brief Check if screen should be shown
+   */
+  bool ShouldShow() const { return !manually_closed_; }
+  
+  /**
+   * @brief Mark as manually closed (don't show again this session)
+   */
+  void MarkManuallyClosed() { manually_closed_ = true; }
+  
+ private:
+  void DrawHeader();
+  void DrawQuickActions();
+  void DrawRecentProjects();
+  void DrawProjectCard(const RecentProject& project, int index);
+  void DrawTemplatesSection();
+  void DrawTipsSection();
+  void DrawWhatsNew();
+  
+  std::vector<RecentProject> recent_projects_;
+  bool manually_closed_ = false;
+  
+  // Callbacks
+  std::function<void()> open_rom_callback_;
+  std::function<void()> new_project_callback_;
+  std::function<void(const std::string&)> open_project_callback_;
+  
+  // UI state
+  int selected_template_ = 0;
+  static constexpr int kMaxRecentProjects = 6;
+  
+  // Animation state
+  float animation_time_ = 0.0f;
+  float header_glow_ = 0.0f;
+  float card_hover_scale_[6] = {1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f};
+  int hovered_card_ = -1;
+};
+
+}  // namespace editor
+}  // namespace yaze
+
+#endif  // YAZE_APP_EDITOR_UI_WELCOME_SCREEN_H_