say per-agent socket where the manager socket is gone

the manager socket no longer exists; ruth's socket is the per-agent one. Fixes the wire-type crate docs, hive-sh4re manager.rs header and README, and two other mentions.

hive-agent/src/web_ui/state.rs

@@ -394,7 +394,7 @@ struct ExtraLink {
 }
 
 /// Best-effort: pull the last 30 messages addressed to us via the
-/// per-agent / manager socket. Empty list on any transport / decode
+/// per-agent socket. Empty list on any transport / decode
 /// failure — the inbox section is decorative, not authoritative.
 async fn recent_inbox(socket: &std::path::Path) -> Vec<hive_sh4re::inbox::InboxRow> {
     const LIMIT: u64 = 30;