Legacy Itemmodels

Automatically generate missing item asset files for mods to ensure compatibility with Minecraft 1.21.4+

Starting from Minecraft 1.21.4, mods are required to include the `assets/(modid)/items` folder with specific item asset JSON files. However, many existing mods only have `assets/(modid)/models/item/` assets and don't provide the new required files, causing compatibility issues.

This mod automatically generates and loads the necessary `items` assets at runtime, allowing older mods to work without manual asset updates.

Ideal for mod developers or pack creators who want to maintain compatibility with 1.21.4+ without rewriting assets.