feat: federation media forwarding WORKING — global rooms router model complete

2-relay test: 5.0s audio, RMS 4748, PASS. Full pipeline verified:
- Room correctly identified as global (hash matching works)
- Federation egress channel created and connected
- GlobalRoomActive signals exchanged between peers
- 300 packets (250 source + 50 FEC) forwarded via tagged datagrams
- Client B on relay B received full 5-second tone from client A on relay A

Added debug logging: is_global check, egress channel creation, per-peer
forwarding with active_rooms diagnostic when no match found. Also logs
egress packet count (first + every 250th).

Multi-hop propagation: GlobalRoomActive signals forwarded to other peers
so A→B→C chain knows about rooms across the full mesh.

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

crates/wzp-relay/src/federation.rs

@@ -144,14 +144,25 @@ impl FederationManager {
         if links.is_empty() {
             return;
         }
-        for link in links.values() {
+        let mut sent = 0u32;
+        for (fp, link) in links.iter() {
             if link.active_rooms.contains(room_name) {
                 let mut tagged = Vec::with_capacity(8 + media_data.len());
                 tagged.extend_from_slice(room_hash);
                 tagged.extend_from_slice(media_data);
-                let _ = link.transport.send_raw_datagram(&tagged);
+                match link.transport.send_raw_datagram(&tagged) {
+                    Ok(()) => sent += 1,
+                    Err(e) => warn!(peer = %link.label, "federation send error: {e}"),
+                }
             }
         }
+        if sent == 0 && !links.is_empty() {
+            // Debug: no peer had this room active
+            let active_rooms: Vec<_> = links.values()
+                .flat_map(|l| l.active_rooms.iter().cloned())
+                .collect();
+            warn!(room = %room_name, peer_count = links.len(), ?active_rooms, "no peer has this room active");
+        }
     }
 
     // ── Trust verification (kept from previous implementation) ──
@@ -191,9 +202,15 @@ pub async fn run_federation_media_egress(
     fm: Arc<FederationManager>,
     mut rx: tokio::sync::mpsc::Receiver<FederationMediaOut>,
 ) {
+    let mut count: u64 = 0;
     while let Some(out) = rx.recv().await {
+        count += 1;
+        if count == 1 || count % 250 == 0 {
+            info!(room = %out.room_name, count, "federation egress: forwarding media");
+        }
         fm.forward_to_peers(&out.room_name, &out.room_hash, &out.data).await;
     }
+    info!(total = count, "federation egress task ended");
 }
 
 // ── Room event dispatcher ──