new `PlayerCamController` script for camera control, enabling mouse-based rotation and player orientation updates.
Added a "Plane" GameObject with `MeshCollider`, `MeshRenderer`, and `MeshFilter` components. Updated the "Cube" GameObject to "Player," applied the new "Grey" material, and adjusted its position.
Modified the `Main Camera` background color and position, and added the `PlayerCamController` script to it. Updated `SceneRoots` and `ProjectSettings.asset` to reflect these changes.
