Bug fixes, new blocks

## **Features & Gameplay**

*   **Beginnings of Modding Support:** Implemented a Content Pack System and dynamic block palette system for modding.

*   **Rails & Minecarts:** Added Rail blocks, Minecart entities, and refactored Block/Item IDs and physics for them. Minecarts don't quite work yet.

*   **Physics Improvements:** Prevented block placement inside the player and allowed jumping when stuck.

*   **Inventory:** Tweaked inventory UI and functionality.

### **Rendering & Graphics**

*   **Culling Fixes:** Corrected voxel face culling with accurate FCC neighbor offsets.

*   **Debug Visuals:** Added visual highlights for aimed voxel faces and culling state details in debug mode.

*   **Textures:** Fixed dynamic UV mapping to preserve original textures.

### **Bug Fixes**

*   Fixed invisible blocks and unknown names in the inventory.

*   Resolved `ReferenceError` for `worldToGrid` and `CHUNK_SIZE`.

*   Fixed `main.tsx` missing function definitions.

*   Corrected entity renderer stride issues.

*   Fixed block removal logic and implemented safer block interaction.