refactor: Update Renderer Logic and Introduce Direct Pixel Access Methods

- Removed direct renderer calls from LoadLinkGraphics and LoadAllGraphicsData to prepare for future renderer refactor.
- Added LockTexture and UnlockTexture methods to IRenderer and SDL2Renderer for direct pixel access, enhancing texture management capabilities.
- Updated CMake configuration to include the new SDL2Renderer source file, ensuring proper integration within the graphics backend.

src/app/gfx/gfx_library.cmake

@@ -15,6 +15,7 @@ set(
   app/gfx/tilemap.cc
   app/gfx/graphics_optimizer.cc
   app/gfx/bpp_format_manager.cc
+  app/gfx/backend/sdl2_renderer.cc
 )
 
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