feat: 添加上游断开时的会议暂停处理逻辑并优化实时转录显示

- 在 `RealtimeAsrSession` 组件中添加 `handleUpstreamPauseError` 方法，处理上游断开时的会议暂停
- 更新 `LocalRealtimeAsrChannel` 类，移除不必要的回调调用
- 优化 `RealtimeMeetingTranscriptCacheServiceImpl` 中的说话人解析逻辑
- 移除 `RealtimeAsrSession` 组件中部分未使用的实时转录显示字段

backend/src/main/java/com/imeeting/service/realtime/impl/LocalRealtimeAsrChannel.java

@@ -513,7 +513,6 @@ public class LocalRealtimeAsrChannel implements RealtimeAsrChannel {
       log.info("上游 ASR websocket 已关闭：meetingId={}, sessionId={}, code={}, reason={}",
         context.getMeetingId(), currentConnectionId(context), statusCode, reason);
       context.getChannelState().remove(STATE_UPSTREAM_SOCKET);
-      context.getCallback().removeMeetingSession(context.getMeetingId());
       context.getCallback().sendFrontendError(context.getMeetingId(),
         "REALTIME_UPSTREAM_CLOSED",
         reason == null || reason.isBlank() ? "上游 ASR WebSocket 已断开" : "上游 ASR WebSocket 已断开: " + reason);
@@ -533,6 +532,7 @@ public class LocalRealtimeAsrChannel implements RealtimeAsrChannel {
           ? "上游 ASR WebSocket 连接异常"
           : "上游 ASR WebSocket 连接异常: " + error.getMessage());
       context.getCallback().closeFrontend(context.getMeetingId(), CloseStatus.SERVER_ERROR);
+      context.getCallback().removeMeetingSession(context.getMeetingId());
     }
   }
 }

backend/src/main/java/com/imeeting/service/realtime/impl/RealtimeMeetingTranscriptCacheServiceImpl.java

@@ -206,7 +206,7 @@ public class RealtimeMeetingTranscriptCacheServiceImpl implements RealtimeMeetin
       return item.getSpeakerName().trim();
     }
     String speakerId = resolveSpeakerId(item);
-    return speakerId == null || speakerId.isBlank() ? null : speakerId;
+    return speakerId == null || speakerId.isBlank() ? null : "未知说话人" + speakerId;
   }
 
   private String resolveSpeakerId(JsonNode sentence) {

frontend/src/pages/business/RealtimeAsrSession.tsx

@@ -442,6 +442,30 @@ export function RealtimeAsrSession() {
     message.error(errorMessage);
   };
 
+  const handleUpstreamPauseError = async (errorMessage: string) => {
+    if (recording && startedAtRef.current) {
+      elapsedOffsetRef.current += Math.floor((Date.now() - startedAtRef.current) / 1000);
+    }
+    setConnecting(false);
+    setRecording(false);
+    setStatusText("上游识别已断开，正在暂停会议...");
+    sessionStartedRef.current = false;
+    wsRef.current?.close();
+    wsRef.current = null;
+    await shutdownAudioPipeline();
+    startedAtRef.current = null;
+    try {
+      const pauseRes = await pauseRealtimeMeeting(meetingId);
+      setSessionStatus(pauseRes.data.data);
+      setElapsedSeconds(elapsedOffsetRef.current);
+      setStatusText("已暂停，可继续会议");
+      message.error(errorMessage);
+    } catch {
+      setStatusText("识别已断开");
+      message.error(errorMessage);
+    }
+  };
+
   const startAudioPipeline = async () => {
     if (!window.isSecureContext || !navigator.mediaDevices?.getUserMedia) {
       throw new Error("当前浏览器环境不支持麦克风访问。请使用 localhost 或 HTTPS 域名访问系统。");
@@ -585,7 +609,11 @@ export function RealtimeAsrSession() {
 
           if ((payload.code || payload.type === "error") && payload.message) {
             setStatusText(payload.message);
+            if (payload.code === "REALTIME_UPSTREAM_CLOSED" || payload.code === "REALTIME_UPSTREAM_ERROR") {
+              void handleUpstreamPauseError(payload.message);
+            } else {
               void handleFatalRealtimeError(payload.message);
+            }
             return;
           }
 
@@ -804,17 +832,17 @@ export function RealtimeAsrSession() {
             <Text type="secondary" style={{ fontSize: 13 }}>
               字数 <strong style={{ color: "#334155" }}>{totalTranscriptChars}</strong>
             </Text>
-            <Text type="secondary" style={{ fontSize: 13 }}>
-              模型 <strong style={{ color: "#334155" }}>{sessionDraft.asrModelName}</strong>
-            </Text>
-            <Text type="secondary" style={{ fontSize: 13 }}>
-              模式 <strong style={{ color: "#334155" }}>{sessionDraft.mode}</strong>
-            </Text>
-            {sessionDraft.hotwords && sessionDraft.hotwords.length > 0 && (
-              <Text type="secondary" style={{ fontSize: 13 }}>
-                热词 <strong style={{ color: "#334155" }}>{sessionDraft.hotwords.length}</strong>
-              </Text>
-            )}
+            {/*<Text type="secondary" style={{ fontSize: 13 }}>*/}
+            {/*  模型 <strong style={{ color: "#334155" }}>{sessionDraft.asrModelName}</strong>*/}
+            {/*</Text>*/}
+            {/*<Text type="secondary" style={{ fontSize: 13 }}>*/}
+            {/*  模式 <strong style={{ color: "#334155" }}>{sessionDraft.mode}</strong>*/}
+            {/*</Text>*/}
+            {/*{sessionDraft.hotwords && sessionDraft.hotwords.length > 0 && (*/}
+            {/*  <Text type="secondary" style={{ fontSize: 13 }}>*/}
+            {/*    热词 <strong style={{ color: "#334155" }}>{sessionDraft.hotwords.length}</strong>*/}
+            {/*  </Text>*/}
+            {/*)}*/}
           </Space>
         )}
       </div>