Addresses minor issues across the engine to improve stability and UI.
- Updates ImGui window size for better rendering
- Adds macro for boolean returns (R_TRUE and R_FALSE)
- Adds missing includes and removes unused code
- Updates shader code to use the new macros and improve readability
Introduces a skysphere entity to the scene.
Creates the skysphere during application initialization and manages its visibility via Z-buffer enabling/disabling in the render system.
The skysphere is now an ECS entity.
The culling thread skips the skybox entity to avoid unnecessary calculations since it's always visible.
The position of the skybox is updated with the active camera.
