fix(student): 修正 WebSocket 连接的频道标识

添加课程 cid 到频道名称中，确保不同课程的连接不冲突

src/views/Student/index.vue

@@ -4468,7 +4468,7 @@ const createWebSocketConnection = async (type = 1) => {
     docSocket.value.gc = true
     providerSocket.value = new YjsRedisProvider(
       api.yweb_socket,
-      'PPT' + props.courseid,
+      'PPT' + props.courseid + props.cid,
       docSocket.value,
       {
         params: { yauth: authToken.value },