refactor(gfx): reorganize graphics includes and introduce new types

- Updated include paths for various graphics-related headers to improve organization and clarity.
- Introduced new types for SNES color, palette, and tile management, enhancing the structure of the graphics subsystem.
- Refactored existing code to utilize the new types, ensuring consistency across the codebase.

Benefits:
- Improves maintainability and readability of the graphics code.
- Facilitates future enhancements and optimizations within the graphics subsystem.

src/app/editor/dungeon/dungeon_object_selector.cc

@@ -5,8 +5,8 @@
 #include <cstring>
 
 #include "app/core/window.h"
-#include "app/gfx/arena.h"
-#include "app/gfx/snes_palette.h"
+#include "app/gfx/resource/arena.h"
+#include "app/gfx/types/snes_palette.h"
 #include "app/gui/canvas.h"
 #include "app/gui/modules/asset_browser.h"
 #include "app/rom.h"