feat: add GetClient helper and ICE candidate callback

Server/ws/hub.go

@@ -242,6 +242,14 @@ func (h *Hub) IsUserConnected(userID int64) bool {
 	return ok
 }
 
+// GetClient returns the client for userID, or nil if not connected.
+// Safe to call from any goroutine.
+func (h *Hub) GetClient(userID int64) *Client {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	return h.clients[userID]
+}
+
 // Register queues a client for registration with the hub.
 func (h *Hub) Register(c *Client) {
 	h.register <- c

Server/ws/hub_test.go

@@ -401,6 +401,28 @@ func TestHub_ConcurrentRegisterUnregister(t *testing.T) {
 	}
 }
 
+// ─── GetClient ───────────────────────────────────────────────────────────────
+
+func TestHub_GetClient(t *testing.T) {
+	hub, _ := newTestHub(t)
+	send := make(chan []byte, 256)
+	client := ws.NewTestClient(hub, 42, send)
+	hub.Register(client)
+	go hub.Run()
+	defer hub.Stop()
+	time.Sleep(10 * time.Millisecond)
+
+	got := hub.GetClient(42)
+	if got == nil {
+		t.Fatal("GetClient(42) returned nil")
+	}
+
+	got2 := hub.GetClient(999)
+	if got2 != nil {
+		t.Fatal("GetClient(999) should return nil")
+	}
+}
+
 // ─── assertion helpers ────────────────────────────────────────────────────────
 
 func assertReceived(t *testing.T, ch <-chan []byte, want []byte, label string) {

Server/ws/voice_handlers.go

@@ -53,6 +53,21 @@ func (h *Hub) SetupICEMonitorForTest(c *Client, channelID int64) {
 	h.setupICEMonitor(c, channelID)
 }
 
+// setupICECallback registers an OnICECandidate handler on the client's
+// PeerConnection to send server-generated ICE candidates to the client.
+func (h *Hub) setupICECallback(c *Client, channelID int64) {
+	pc := c.getPC()
+	if pc == nil {
+		return
+	}
+	pc.OnICECandidate(func(candidate *webrtc.ICECandidate) {
+		if candidate == nil {
+			return // gathering complete
+		}
+		c.sendMsg(buildVoiceICE(channelID, candidate.ToJSON()))
+	})
+}
+
 // handleVoiceJoin processes a voice_join message.
 // 1. Parses channel_id.
 // 2. Checks CONNECT_VOICE permission.
@@ -129,6 +144,7 @@ func (h *Hub) handleVoiceJoin(c *Client, payload json.RawMessage) {
 	if pc != nil {
 		h.setupOnTrack(c, channelID)
 		h.setupICEMonitor(c, channelID)
+		h.setupICECallback(c, channelID)
 	}
 
 	state, err := h.db.GetVoiceState(c.userID)