fix(camera): keep streaming active during recording

cmvr-es/devices/camera/uvc_camera/src/uvc_camera.cpp

@@ -1178,10 +1178,22 @@ bool UVCCamera::startStreaming()
             stream_thread_.reset();
         }
     }
+
+    // A recording session may already own the encoder worker. The streaming
+    // state still has to reflect the new client lease so stopping recording
+    // does not terminate the worker while clients are consuming frames.
+    state_.is_streaming = true;
     //开启流采集线程
     if (!stream_thread_) {
-        state_.is_streaming = true;
+        try {
             stream_thread_ = make_shared<thread>(&UVCCamera::streaming_worker_, this);
+        } catch (const std::exception& e) {
+            state_.is_streaming = stream_count_ > 0;
+            state_.is_error = true;
+            state_.error_message = "failed to start streaming worker: " + std::string(e.what());
+            CMVR_LOG(ERROR) << "[UVCCamera] (startStreaming): " << state_.error_message;
+            return false;
+        }
 
         //延时100ms，等待流线程获取图像
         std::this_thread::sleep_for(std::chrono::milliseconds(100));