Spawn Dimension Choice

Mod Introduction:

This mod adds two new buttons to the world creation interface. 
On the world creation page, below the "Allow Cheats" option, there are two buttons: "Birth Dimension Preset" on the left and "Custom Dimension ID" on the right.  
- The left button lets players choose from vanilla dimensions (Overworld, Nether, End) as their spawn dimension.  
- The right button allows selecting spawn dimensions from other mods by entering custom dimension IDs.  

Safety Features:

The mod includes safety measures for the spawn dimension, both toggleable in the config file:  
1. If the player spawns with no blocks under their feet, a 5x5 platform will generate.  
2. If the player spawns inside a solid block, blocks within a 5x4x5 area centered on the player will be cleared.