Implement microphone selection feature in voice preview

- Add audio input selection to DebugVoicePanel, allowing users to choose their microphone device.
- Update useVoicePreview hook to manage available audio inputs and selected device state.
- Enhance device enumeration and selection handling to ensure a seamless user experience during voice interactions.

frontend/src/components/pages/AssistantPage.tsx

@@ -1857,6 +1857,9 @@ function DebugVoicePanel({
     micWarning,
     localStream,
     messages,
+    audioInputs,
+    selectedDeviceId,
+    setSelectedDeviceId,
     sendText,
     connect,
     disconnect,
@@ -1942,6 +1945,33 @@ function DebugVoicePanel({
             </p>
           </div>
 
+          <div className="relative w-full max-w-xs">
+            <Select
+              value={selectedDeviceId || "default"}
+              onValueChange={(value) =>
+                setSelectedDeviceId(value === "default" ? "" : value)
+              }
+              disabled={recording}
+            >
+              <SelectTrigger
+                size="sm"
+                className="w-full justify-center gap-2 rounded-full border-hairline bg-canvas-soft text-xs text-muted-foreground"
+                aria-label="选择麦克风"
+              >
+                <Mic size={13} className="shrink-0 text-muted-soft" />
+                <SelectValue placeholder="默认麦克风" />
+              </SelectTrigger>
+              <SelectContent>
+                <SelectItem value="default">默认麦克风</SelectItem>
+                {audioInputs.map((device, index) => (
+                  <SelectItem key={device.deviceId} value={device.deviceId}>
+                    {device.label || `麦克风 ${index + 1}`}
+                  </SelectItem>
+                ))}
+              </SelectContent>
+            </Select>
+          </div>
+
           <Button
             disabled={!assistantId || status === "connecting"}
             onClick={() => {

frontend/src/hooks/use-voice-preview.ts

@@ -75,6 +75,10 @@ export function useVoicePreview(assistantId: string | null) {
   const [micWarning, setMicWarning] = useState<string | null>(null);
   const [localStream, setLocalStream] = useState<MediaStream | null>(null);
   const [messages, setMessages] = useState<ChatMessage[]>([]);
+  // 可选麦克风列表与当前选择(空串表示交给浏览器选默认设备)
+  const [audioInputs, setAudioInputs] = useState<MediaDeviceInfo[]>([]);
+  const [selectedDeviceId, setSelectedDeviceId] = useState<string>("");
+  const selectedDeviceIdRef = useRef("");
   const audioRef = useRef<HTMLAudioElement | null>(null);
   const pcRef = useRef<RTCPeerConnection | null>(null);
   const wsRef = useRef<WebSocket | null>(null);
@@ -83,6 +87,40 @@ export function useVoicePreview(assistantId: string | null) {
   const startingRef = useRef(false);
   const messageSeqRef = useRef(0);
 
+  // 枚举可用麦克风。未授权前 label 为空,授权(连接)后再刷新即可拿到名称。
+  const refreshDevices = useCallback(async () => {
+    if (!navigator.mediaDevices?.enumerateDevices) return;
+    try {
+      const devices = await navigator.mediaDevices.enumerateDevices();
+      const inputs = devices.filter((d) => d.kind === "audioinput");
+      setAudioInputs(inputs);
+      // 选中的设备已被拔出时,回退到浏览器默认设备
+      if (
+        selectedDeviceIdRef.current &&
+        !inputs.some((d) => d.deviceId === selectedDeviceIdRef.current)
+      ) {
+        setSelectedDeviceId("");
+      }
+    } catch {
+      /* 忽略枚举失败 */
+    }
+  }, []);
+
+  // connect/refreshDevices 在回调里读最新选择,避免把它们挂进依赖反复重建
+  useEffect(() => {
+    selectedDeviceIdRef.current = selectedDeviceId;
+  }, [selectedDeviceId]);
+
+  useEffect(() => {
+    if (!navigator.mediaDevices?.enumerateDevices) return;
+    // eslint-disable-next-line react-hooks/set-state-in-effect
+    void refreshDevices();
+    navigator.mediaDevices.addEventListener("devicechange", refreshDevices);
+    return () => {
+      navigator.mediaDevices.removeEventListener("devicechange", refreshDevices);
+    };
+  }, [refreshDevices]);
+
   const releaseResources = useCallback(() => {
     const ws = wsRef.current;
     wsRef.current = null;
@@ -151,13 +189,20 @@ export function useVoicePreview(assistantId: string | null) {
     let stream: MediaStream | null = null;
     if (window.isSecureContext && navigator.mediaDevices?.getUserMedia) {
       try {
+        const audioConstraints: MediaTrackConstraints = {
+          echoCancellation: true,
+          noiseSuppression: true,
+          autoGainControl: true,
+        };
+        // 指定了具体设备就强制用它,否则交给浏览器选默认麦克风
+        if (selectedDeviceIdRef.current) {
+          audioConstraints.deviceId = { exact: selectedDeviceIdRef.current };
+        }
         stream = await navigator.mediaDevices.getUserMedia({
-          audio: {
+          audio: audioConstraints,
-            echoCancellation: true,
-            noiseSuppression: true,
-            autoGainControl: true,
-          },
         });
+        // 授权后 label 才可见,刷新列表把真实设备名补上
+        void refreshDevices();
       } catch (mediaError) {
         setMicWarning(microphoneErrorMessage(mediaError));
       }
@@ -319,7 +364,7 @@ export function useVoicePreview(assistantId: string | null) {
     } finally {
       startingRef.current = false;
     }
-  }, [assistantId, fail]);
+  }, [assistantId, fail, refreshDevices]);
 
   // 发送文字消息:后端先打断当前播报,再按用户输入触发新回复。
   // 成功返回 true;通道未就绪(未开始对话/连接中)返回 false。
@@ -340,6 +385,9 @@ export function useVoicePreview(assistantId: string | null) {
     micWarning,
     localStream,
     messages,
+    audioInputs,
+    selectedDeviceId,
+    setSelectedDeviceId,
     sendText,
     connect,
     disconnect,