Updated game structure

src/states/State.h

@@ -29,6 +29,8 @@ struct StateContext {
     int logoSmallW = 0;
     int logoSmallH = 0;
     SDL_Texture* backgroundTex = nullptr;
+    // backgroundTex is set once in `main.cpp` and passed to states via this context.
+    // Prefer reading this field instead of relying on any `extern SDL_Texture*` globals.
     SDL_Texture* blocksTex = nullptr;
 
     // Audio / SFX - forward declared types in main