epic: refactor SDL2_Renderer usage to IRenderer and queued texture rendering

- Updated the testing guide to clarify the testing framework's organization and execution methods, improving user understanding.
- Refactored CMakeLists to include new platform-specific files, ensuring proper integration of the rendering backend.
- Modified main application files to utilize the new IRenderer interface, enhancing flexibility in rendering operations.
- Implemented deferred texture management in various components, allowing for more efficient graphics handling and improved performance.
- Introduced new methods for texture creation and updates, streamlining the rendering process across the application.
- Enhanced logging and error handling in the rendering pipeline to facilitate better debugging and diagnostics.

src/app/editor/dungeon/dungeon_object_interaction.h

@@ -30,6 +30,7 @@ class DungeonObjectInteraction {
   // Selection rectangle (like OverworldEditor)
   void DrawObjectSelectRect();
   void SelectObjectsInRect();
+  void DrawSelectionHighlights();  // Draw highlights for selected objects
   
   // Drag and select box functionality
   void DrawSelectBox();