[Enhancement] Support loading mods inside folders to help organize large modpacks

[FlyingMyLife]

This would make it easier to organize large modpacks into categorized folders (e.g., mods/performance/, mods/optional/, etc).

Currently, Fabric Loader only loads .jar files from the top level mods/ directory. For large modpacks, this can become hard to maintain. Many modpack developers and users would benefit from being able to group mods. Like that:

mods/
├── main/
│   ├── create.jar
│   └── (...)
├── optimization/
│   └── sodium.jar
│   └── (...)
└── visuals/
    └── iris.jar
    └── (...)

Suggested solution

Use Depth-First Search (DFS) to recursively scan the mods/ folder for .jar files, allowing mods to be organized in subfolders. Optionally, include a depth limit to prevent excessive traversal.

Its not that hard to implement, but it would be a great update for modpack creators

[Raik176]

You can already do this using the fabric.addMods system property (although you have to add each directory manually). If you do not want to use it, you could also just prefix each file name with the group for organization (e.g. optimization_sodium-0.0.0.jar)

[Poopooracoocoo]

#81 was already opened for this suggestion. I like the approach of a JVM argument like #994 implements.