Add `hf knowledge-base` group: list/get/tree/topics, create/update/delete, link/unlink to projects, and add/update/delete for topics, categories and facts. Mirrors the project command style (flag parsing, JSON/table output, token resolution). Registered in the dispatcher and the help surface, gated on the knowledge-base.* permissions. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>