Add support for Xfyun ASR and TTS services in the backend

- Introduce new Xfyun ASR and TTS services, enabling integration with iFlytek's voice recognition and synthesis capabilities.
- Update AssistantConfig model to include interface types for STT and TTS.
- Enhance credential testing to validate Xfyun credentials.
- Modify service factory to create Xfyun services based on configuration.
- Update README with new configuration details for Xfyun integration.
- Add new frontend components for visualizing audio streams and managing user interactions.

frontend/src/components/pages/AssistantPage.tsx

@@ -60,6 +60,7 @@ import { AuraVisualizer } from "@/components/ui/aura-visualizer";
 import { NebulaVisualizer } from "@/components/ui/nebula-visualizer";
 import { SpectrumVisualizer } from "@/components/ui/spectrum-visualizer";
 import { WaveVisualizer } from "@/components/ui/wave-visualizer";
+import { WaveformTimelinePanel } from "@/components/ui/waveform-timeline";
 import {
   Card,
   CardContent,
@@ -1856,6 +1857,7 @@ function DebugVoicePanel({
     error,
     micWarning,
     localStream,
+    remoteStream,
     messages,
     audioInputs,
     selectedDeviceId,
@@ -2032,6 +2034,13 @@ function DebugVoicePanel({
           </Button>
         </div>
       </div>
+
+      {/* 底部双轨波形:用户麦克风 + 助手音频,可折叠 */}
+      <WaveformTimelinePanel
+        userStream={localStream}
+        agentStream={remoteStream}
+        active={status === "connected"}
+      />
     </div>
   );
 }