Docs: FEDERATION.md per FEP-67ff
Documents Klonkt federation surface (AP S2S+C2S, WebFinger, HTTP Signatures, NodeInfo 2.1, OAuth+PKCE), activities/object types, Mastodon extension terms, supported FEPs (67ff, f1d5). Under-consideration section flags DRAFTs and the WITHDRAWN status of FEP-5624.
Co-Authored-By: Claude Opus 4.8 <noreply@…>