Function peer_federation_token 

pub fn peer_federation_token(
    relay_state: &Value,
    peer_handle: &str,
    relay_url: &str,
) -> String

The slot_token of a peer’s pinned federation endpoint on relay_url, or "" if there’s no such endpoint (or it hasn’t acked yet).

RFC-006 Part B: the canonical way to carry a peer’s already-arrived reply token forward across a re-pin. It replaces the old flat peers[h].slot_token read — which Part B (#268) stopped writing, so any dial path still reading it now reads "" and silently wipes the peer’s reply token on re-dial. Both dial paths (cli::pairing and the MCP tool_dial) route through here so they can’t drift apart again.