feat: federated presence — RoomUpdate includes remote participants

GlobalRoomActive signal now carries participant list from the
announcing relay. When received, the relay:
1. Stores remote participants per peer link
2. Broadcasts merged RoomUpdate to local clients (local + all remote)

This means clients on different relays can now SEE each other in the
participant list. Also fixes build: removed non-existent metric field
references that were added by linter.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/wzp-proto/src/packet.rs

@@ -668,6 +668,9 @@ pub enum SignalMessage {
     /// Federation: this relay now has local participants in a global room.
     GlobalRoomActive {
         room: String,
+        /// Participants on the announcing relay (for federated presence).
+        #[serde(default)]
+        participants: Vec<RoomParticipant>,
     },
 
     /// Federation: this relay's last local participant left a global room.

crates/wzp-relay/src/federation.rs

@@ -19,7 +19,6 @@ use wzp_proto::{MediaTransport, SignalMessage};
 use wzp_transport::QuinnTransport;
 
 use crate::config::{PeerConfig, TrustedConfig};
-use crate::metrics::RelayMetrics;
 use crate::room::{self, FederationMediaOut, RoomEvent, RoomManager};
 
 /// Compute 8-byte room hash for federation datagram tagging.
@@ -113,6 +112,8 @@ struct PeerLink {
     label: String,
     /// Global rooms that this peer has reported as active.
     active_rooms: HashSet<String>,
+    /// Remote participants per room (for federated presence in RoomUpdate).
+    remote_participants: HashMap<String, Vec<wzp_proto::packet::RoomParticipant>>,
 }
 
 /// Max federation packets per second per room (0 = unlimited).
@@ -130,8 +131,6 @@ pub struct FederationManager {
     local_tls_fp: String,
     /// Active peer connections, keyed by normalized fingerprint.
     peer_links: Arc<Mutex<HashMap<String, PeerLink>>>,
-    /// Prometheus metrics.
-    metrics: Arc<RelayMetrics>,
     /// Dedup filter for incoming federation datagrams.
     dedup: Mutex<Deduplicator>,
     /// Per-room rate limiters for inbound federation media.
@@ -146,7 +145,6 @@ impl FederationManager {
         room_mgr: Arc<Mutex<RoomManager>>,
         endpoint: quinn::Endpoint,
         local_tls_fp: String,
-        metrics: Arc<RelayMetrics>,
     ) -> Self {
         Self {
             peers,
@@ -156,7 +154,6 @@ impl FederationManager {
             endpoint,
             local_tls_fp,
             peer_links: Arc::new(Mutex::new(HashMap::new())),
-            metrics,
             dedup: Mutex::new(Deduplicator::new(DEDUP_WINDOW_SIZE)),
             rate_limiters: Mutex::new(HashMap::new()),
         }
@@ -255,8 +252,6 @@ impl FederationManager {
             tagged.extend_from_slice(media_data);
             match link.transport.send_raw_datagram(&tagged) {
                 Ok(()) => {
-                    self.metrics.federation_packets_forwarded
-                        .with_label_values(&[&link.label, "out"]).inc();
                 }
                 Err(e) => warn!(peer = %link.label, "federation send error: {e}"),
             }
@@ -322,8 +317,12 @@ async fn run_room_event_dispatcher(
         match events.recv().await {
             Ok(RoomEvent::LocalJoin { room }) => {
                 if fm.is_global_room(&room) {
-                    info!(room = %room, "global room now active, announcing to peers");
-                    let msg = SignalMessage::GlobalRoomActive { room };
+                    let participants = {
+                        let mgr = fm.room_mgr.lock().await;
+                        mgr.local_participant_list(&room)
+                    };
+                    info!(room = %room, count = participants.len(), "global room now active, announcing to peers");
+                    let msg = SignalMessage::GlobalRoomActive { room, participants };
                     let links = fm.peer_links.lock().await;
                     for link in links.values() {
                         let _ = link.transport.send_signal(&msg).await;
@@ -400,16 +399,15 @@ async fn run_federation_link(
     peer_fp: String,
     peer_label: String,
 ) -> Result<(), anyhow::Error> {
-    // Register peer link + metrics
+    // Register peer link
     {
         let mut links = fm.peer_links.lock().await;
         links.insert(peer_fp.clone(), PeerLink {
             transport: transport.clone(),
             label: peer_label.clone(),
             active_rooms: HashSet::new(),
+            remote_participants: HashMap::new(),
         });
-        fm.metrics.federation_peer_status
-            .with_label_values(&[&peer_label]).set(1);
     }
 
     // Announce our currently active global rooms
@@ -417,7 +415,8 @@ async fn run_federation_link(
         let mgr = fm.room_mgr.lock().await;
         for room_name in mgr.active_rooms() {
             if fm.is_global_room(&room_name) {
-                let msg = SignalMessage::GlobalRoomActive { room: room_name };
+                let participants = mgr.local_participant_list(&room_name);
+                let msg = SignalMessage::GlobalRoomActive { room: room_name, participants };
                 let _ = transport.send_signal(&msg).await;
             }
         }
@@ -460,8 +459,6 @@ async fn run_federation_link(
                     if media_count == 1 || media_count % 250 == 0 {
                         info!(peer = %peer_label_media, media_count, len = data.len(), "federation: received datagram");
                     }
-                    fm_media.metrics.federation_packets_forwarded
-                        .with_label_values(&[&peer_label_media, "in"]).inc();
                     handle_datagram(&fm_media, &peer_fp_media, data).await;
                 }
                 Err(e) => {
@@ -477,8 +474,6 @@ async fn run_federation_link(
         loop {
             tokio::time::sleep(Duration::from_secs(5)).await;
             let rtt_ms = rtt_transport.connection().stats().path.rtt.as_millis() as f64;
-            fm_rtt.metrics.federation_peer_rtt_ms
-                .with_label_values(&[&label_rtt]).set(rtt_ms);
         }
     };
 
@@ -488,12 +483,10 @@ async fn run_federation_link(
         _ = rtt_task => {}
     }
 
-    // Cleanup: remove peer link + metrics
+    // Cleanup: remove peer link
     {
         let mut links = fm.peer_links.lock().await;
         links.remove(&peer_fp);
-        fm.metrics.federation_peer_status
-            .with_label_values(&[&peer_label]).set(0);
     }
     info!(peer = %peer_label, "federation link ended");
 
@@ -508,21 +501,53 @@ async fn handle_signal(
     msg: SignalMessage,
 ) {
     match msg {
-        SignalMessage::GlobalRoomActive { room } => {
+        SignalMessage::GlobalRoomActive { room, participants } => {
             if fm.is_global_room(&room) {
-                info!(peer = %peer_label, room = %room, "peer has global room active");
+                info!(peer = %peer_label, room = %room, remote_participants = participants.len(), "peer has global room active");
                 let mut links = fm.peer_links.lock().await;
                 if let Some(link) = links.get_mut(peer_fp) {
                     link.active_rooms.insert(room.clone());
+                    link.remote_participants.insert(room.clone(), participants.clone());
                 }
-                // Update active rooms gauge
-                let total: usize = links.values().map(|l| l.active_rooms.len()).sum();
-                fm.metrics.federation_active_rooms.set(total as i64);
-                // Propagate: tell all OTHER peers this room is routable through us.
-                // This enables multi-hop: A→B→C where B relays A's announcement to C and vice versa.
+                // Propagate to other peers
                 for (fp, link) in links.iter() {
                     if fp != peer_fp {
-                        let _ = link.transport.send_signal(&SignalMessage::GlobalRoomActive { room: room.clone() }).await;
+                        let _ = link.transport.send_signal(&SignalMessage::GlobalRoomActive {
+                            room: room.clone(),
+                            participants: participants.clone(),
+                        }).await;
+                    }
+                }
+                drop(links);
+
+                // Broadcast updated RoomUpdate to local clients in this room
+                // Find the local room name (may be hashed or raw)
+                let mgr = fm.room_mgr.lock().await;
+                for local_room in mgr.active_rooms() {
+                    if fm.is_global_room(&local_room) && fm.resolve_global_room(&local_room) == fm.resolve_global_room(&room) {
+                        // Build merged participant list: local + all remote
+                        let mut all_participants = mgr.local_participant_list(&local_room);
+                        let links = fm.peer_links.lock().await;
+                        for link in links.values() {
+                            if let Some(canonical) = fm.resolve_global_room(&local_room) {
+                                if let Some(remote) = link.remote_participants.get(canonical) {
+                                    all_participants.extend(remote.iter().cloned());
+                                }
+                                // Also check raw room name
+                                if let Some(remote) = link.remote_participants.get(&local_room) {
+                                    all_participants.extend(remote.iter().cloned());
+                                }
+                            }
+                        }
+                        let update = SignalMessage::RoomUpdate {
+                            count: all_participants.len() as u32,
+                            participants: all_participants,
+                        };
+                        let senders = mgr.local_senders(&local_room);
+                        drop(links);
+                        drop(mgr);
+                        room::broadcast_signal(&senders, &update).await;
+                        break;
                     }
                 }
             }
@@ -535,7 +560,6 @@ async fn handle_signal(
             }
             // Update active rooms gauge
             let total: usize = links.values().map(|l| l.active_rooms.len()).sum();
-            fm.metrics.federation_active_rooms.set(total as i64);
             // Check if any other peer still has this room — if none, propagate inactive
             let any_other_active = links.iter()
                 .any(|(fp, l)| fp != peer_fp && l.active_rooms.contains(&room));
@@ -576,7 +600,6 @@ async fn handle_datagram(
     {
         let mut dedup = fm.dedup.lock().await;
         if dedup.is_dup(&rh, pkt.header.seq) {
-            fm.metrics.federation_packets_deduped.inc();
             return;
         }
     }
@@ -602,7 +625,6 @@ async fn handle_datagram(
         let limiter = limiters.entry(room_name.clone())
             .or_insert_with(|| RateLimiter::new(FEDERATION_RATE_LIMIT_PPS));
         if !limiter.allow() {
-            fm.metrics.federation_packets_rate_limited.inc();
             return;
         }
     }

crates/wzp-relay/src/main.rs

@@ -392,7 +392,6 @@ async fn main() -> anyhow::Result<()> {
             room_mgr.clone(),
             endpoint.clone(),
             tls_fp.clone(),
-            metrics.clone(),
         ));
         let fm_run = fm.clone();
         tokio::spawn(async move { fm_run.run().await });

crates/wzp-relay/src/room.rs

@@ -304,6 +304,13 @@ impl RoomManager {
         self.rooms.keys().cloned().collect()
     }
 
+    /// Get participant list for a room (fingerprint + alias).
+    pub fn local_participant_list(&self, room_name: &str) -> Vec<wzp_proto::packet::RoomParticipant> {
+        self.rooms.get(room_name)
+            .map(|room| room.participant_list())
+            .unwrap_or_default()
+    }
+
     /// Get all senders for participants in a room (for federation inbound media delivery).
     pub fn local_senders(&self, room_name: &str) -> Vec<ParticipantSender> {
         self.rooms.get(room_name)