refactor(simulator): enhance mobile simulator UI with updated styles, improved security policies, and WebRTC signaling support

Backend/realtime/gateway.ts

@@ -19,6 +19,13 @@ const commandAckSchema = z.object({
   error: z.string().optional(),
 });
 
+const webrtcSignalSchema = z.object({
+  toDeviceId: z.string().uuid(),
+  streamSessionId: z.string().uuid(),
+  signalType: z.enum(['offer', 'answer', 'candidate', 'hangup']),
+  data: z.record(z.string(), z.unknown()).nullable().optional(),
+});
+
 const roomForDevice = (deviceId: string): string => `device:${deviceId}`;
 
 let io: SocketIOServer | null = null;
@@ -286,6 +293,34 @@ export const setupRealtimeGateway = (server: HttpServer): SocketIOServer => {
       });
     });
 
+    socket.on('webrtc:signal', async (input) => {
+      const parsed = webrtcSignalSchema.safeParse(input);
+
+      if (!parsed.success) {
+        socket.emit('error:webrtc_signal', {
+          message: 'Invalid WebRTC signal payload',
+          errors: parsed.error.flatten(),
+        });
+        return;
+      }
+
+      const targetDevice = await db.query.devices.findFirst({
+        where: and(eq(devices.id, parsed.data.toDeviceId), eq(devices.userId, auth.userId)),
+      });
+
+      if (!targetDevice) {
+        socket.emit('error:webrtc_signal', { message: 'Target device not found for this account' });
+        return;
+      }
+
+      io?.to(roomForDevice(parsed.data.toDeviceId)).emit('webrtc:signal', {
+        fromDeviceId: auth.deviceId,
+        streamSessionId: parsed.data.streamSessionId,
+        signalType: parsed.data.signalType,
+        data: parsed.data.data ?? null,
+      });
+    });
+
     socket.on('disconnect', async () => {
       // Small delay allows fast reconnects to reuse presence without flapping.
       setTimeout(async () => {