Add mock data and unit tests for Channels and Members APIs

test/mocks/Member.ts

@@ -0,0 +1,15 @@
+export const mockMember = {
+  sessionId: 'session-123',
+  screenName: 'Test User',
+  role: 'Presenter',
+  streams: [
+    {
+      type: 'video',
+      uri: 'pcast://example.com/stream-id-123',
+      audioState: 'active',
+      videoState: 'active'
+    }
+  ],
+  state: 'active',
+  lastUpdate: Date.now()
+};