refactor: Restructure file dialog handling and introduce utility classes

- Updated file dialog references across the application to utilize a new `util::FileDialogWrapper` for consistent file handling.
- Refactored existing code to replace direct calls to `core::FileDialogWrapper` with the new utility class, enhancing modularity and maintainability.
- Introduced `util::PlatformPaths` for cross-platform directory management, ensuring consistent access to user directories and application data paths.
- Added new utility functions for file operations, improving the overall file handling capabilities within the application.
- Updated CMake configurations to include new utility source files, streamlining the build process.

src/app/gfx/arena.h

@@ -8,7 +8,7 @@
 #include <unordered_map>
 #include <vector>
 
-#include "app/core/platform/sdl_deleter.h"
+#include "util/sdl_deleter.h"
 #include "app/gfx/background_buffer.h"
 
 namespace yaze {
@@ -177,11 +177,11 @@ class Arena {
   std::array<gfx::Bitmap, 223> gfx_sheets_;
 
   std::unordered_map<SDL_Texture*,
-                     std::unique_ptr<SDL_Texture, core::SDL_Texture_Deleter>>
+                     std::unique_ptr<SDL_Texture, util::SDL_Texture_Deleter>>
       textures_;
 
   std::unordered_map<SDL_Surface*,
-                     std::unique_ptr<SDL_Surface, core::SDL_Surface_Deleter>>
+                     std::unique_ptr<SDL_Surface, util::SDL_Surface_Deleter>>
       surfaces_;
 
   // Resource pooling for efficient memory management