Add Mod Metadata to Patch OTRs

We should add the ability to add metadata to patch OTRs such as: name, author, version number and an icon.

We should do something similar to what Minecraft does. Having a file for the metadata and one for the icon.

The issue names no files, tests, or entry points. Start by locating how patch OTRs are generated and how existing OTR content is structured. Define the metadata file format, supported fields, icon handling, and a clear validation path before implementation; done means generated patch OTRs expose the requested metadata.

Written by the indexing model from the issue text.