VR-UI

* **Description**: Because traditional 2D overlays don't work in VR (they sit too close to the eyes), this module allows the engine to render UI elements as "World Space" objects or "Floating Panels."
* **Acceptance Criteria**:
* UI must be rendered onto a 3D quad or texture positioned in the game world, not directly to the screen pixels.
* The controller's "pointer" must be able to interact with buttons by shooting a ray and detecting collisions with the UI plane.
* The UI should correctly respect depth (e.g., a wall should be able to hide a UI menu) to maintain visual immersion.