docs: document interface.marketplace.categories

[Educg550]

Summary

Documents the new interface.marketplace.categories YAML syntax introduced upstream, which allows administrators to define custom Agent Marketplace categories from librechat.yaml.

What changed

• Extended the ## marketplace section in content/docs/configuration/librechat_yaml/object_structure/interface.mdx:
  • Added categories to the marketplace Sub-keys table.
  • Added a new ### categories subsection covering enableDefaultCategories, list, and list item shape (value, description).
  • Added a full nested YAML example.
  • Added a note describing sync-on-startup behavior (custom categories removed from the YAML are deleted from the database; default categories are never deleted, only hidden).

Related upstream

• LibreChat PR: feat: Agent Marketplace categories synced through librechat.yaml danny-avila/LibreChat#13309
• Issue: [Enhancement]: Custom Agent Categories danny-avila/LibreChat#9287

[vercel]

@Educg550 is attempting to deploy a commit to the LibreChat's projects Team on Vercel.

A member of the Team first needs to authorize it.