feat: 实现摄像头和麦克风设备选择功能

- 新增 useDeviceList hook，枚举音视频输入设备并监听热插拔
- CameraManager/MicManager 的 startCamera/startMic 支持可选 deviceId 参数
- useVisionSession 集成设备选择：授权后自动枚举、切换设备时热重启
- 连接后显示设备下拉选择器，未连接时隐藏（避免未授权时空列表）
- SessionConfig 新增 cameraDeviceId/micDeviceId 持久化到 localStorage

frontend/src/App.css

@@ -644,12 +644,6 @@ body {
   transition: all var(--transition-fast);
 }
 
-.ai-vision-indicator--active {
-  color: var(--color-success);
-  background: rgba(52, 211, 153, 0.15);
-  animation: pulse 2s cubic-bezier(0.25, 0.46, 0.45, 0.94) infinite;
-}
-
 /* ---- 视频控制栏 ---- */
 
 .video-controls {
@@ -750,16 +744,6 @@ body {
   gap: 10px;
 }
 
-.chat-panel-header__mode {
-  font-size: 0.68rem;
-  font-weight: 500;
-  color: var(--color-success);
-  background: rgba(52, 211, 153, 0.08);
-  padding: 3px 10px;
-  border-radius: 12px;
-  letter-spacing: 0.02em;
-}
-
 /* ---- Scenario Quick Selector (chat header) ---- */
 .scenario-selector {
   appearance: none;
@@ -1473,38 +1457,6 @@ body {
   outline-offset: 1px;
 }
 
-/* Mode switcher */
-.video-controls__mode {
-  display: flex;
-  gap: 2px;
-  background: var(--color-surface-2);
-  border-radius: var(--radius-sm);
-  padding: 2px;
-  justify-content: center;
-}
-
-.mode-btn {
-  background: none;
-  border: none;
-  color: var(--color-text-muted);
-  font-size: 0.7rem;
-  font-weight: 500;
-  padding: 5px 12px;
-  border-radius: 6px;
-  cursor: pointer;
-  transition: all var(--transition-fast);
-  white-space: nowrap;
-}
-
-.mode-btn:hover {
-  color: var(--color-text);
-}
-
-.mode-btn--active {
-  background: var(--color-primary);
-  color: white;
-}
-
 /* ---- Text-only mode (video ended, chat preserved) ---- */
 
 .video-controls__text-only {

frontend/src/App.tsx

@@ -24,9 +24,6 @@ import type { Theme } from "./types";
 import type { UserScenario } from "./lib/api/scenarios";
 import "./App.css";
 
-/** AI 视觉模式 */
-type VisionMode = "realtime" | "ondemand" | "chat";
-
 /** 内部组件，确保在 I18nContext.Provider 内部使用 hooks */
 function AppContent() {
   const { isAuthenticated, isLoading, user, logout, accessToken } = useAuth();
@@ -36,7 +33,6 @@ function AppContent() {
   const [theme, setTheme] = useState<Theme>(loadTheme);
   const [elapsed, setElapsed] = useState(0);
   const [sidebarOpen, setSidebarOpen] = useState(false);
-  const [visionMode, setVisionMode] = useState<VisionMode>("ondemand");
   const timerRef = useRef<ReturnType<typeof setInterval> | null>(null);
 
   // ---- 自建情景管理 ----
@@ -91,8 +87,6 @@ function AppContent() {
     config,
     updateConfig,
     stats,
-    mode,
-    isObserving,
     startSession,
     stopSession,
     stopVideo,
@@ -102,6 +96,9 @@ function AppContent() {
     toggleCamera,
     toggleMic,
     sendTextMessage,
+    cameras,
+    mics,
+    switchDevice,
   } = useVisionSession(accessToken, activeSessionId);
 
   const isConnected = connectionStatus === "connected";
@@ -365,13 +362,13 @@ function AppContent() {
               <div className="detail-badge">HD</div>
             )}
             {/* AI 视觉状态指示 */}
-            {isConnected && visionMode !== "chat" && (
-              <div className={`ai-vision-indicator ${isObserving ? "ai-vision-indicator--active" : ""}`}>
+            {isConnected && (
+              <div className="ai-vision-indicator">
                 <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
                   <path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z" />
                   <circle cx="12" cy="12" r="3" />
                 </svg>
-                <span>{isObserving ? tr("video.observing") : "AI"}</span>
+                <span>AI</span>
               </div>
             )}
             {isSpeaking && (
@@ -412,42 +409,6 @@ function AppContent() {
                 <button className="btn btn--primary btn--lg" onClick={startSession}>
                   {connectionStatus === "connecting" ? tr("controls.connecting") : tr("controls.startVideo")}
                 </button>
-                {/* 设备选择器 */}
-                <div className="video-controls__devices">
-                  <div className="device-select-wrapper">
-                    <label className="device-select-label">📷 {tr("controls.device.camera")}</label>
-                    <select className="device-select" defaultValue="default">
-                      <option value="default">{tr("controls.device.default")}</option>
-                    </select>
-                  </div>
-                  <div className="device-select-wrapper">
-                    <label className="device-select-label">🎤 {tr("controls.device.mic")}</label>
-                    <select className="device-select" defaultValue="default">
-                      <option value="default">{tr("controls.device.default")}</option>
-                    </select>
-                  </div>
-                </div>
-                {/* 模式切换器 */}
-                <div className="video-controls__mode">
-                  <button
-                    className={`mode-btn ${visionMode === "realtime" ? "mode-btn--active" : ""}`}
-                    onClick={() => setVisionMode("realtime")}
-                  >
-                    {tr("controls.mode.realtime")}
-                  </button>
-                  <button
-                    className={`mode-btn ${visionMode === "ondemand" ? "mode-btn--active" : ""}`}
-                    onClick={() => setVisionMode("ondemand")}
-                  >
-                    {tr("controls.mode.ondemand")}
-                  </button>
-                  <button
-                    className={`mode-btn ${visionMode === "chat" ? "mode-btn--active" : ""}`}
-                    onClick={() => setVisionMode("chat")}
-                  >
-                    {tr("controls.mode.chat")}
-                  </button>
-                </div>
               </>
             ) : isCameraOn ? (
               <>
@@ -467,16 +428,14 @@ function AppContent() {
                   >
                     🎤
                   </button>
-                  {/* 识别画面按钮（按需模式下显示） */}
-                  {visionMode === "ondemand" && (
-                    <button
-                      className="btn--recognize"
-                      onClick={handleRecognize}
-                      disabled={isProcessing}
-                    >
-                      🔍 {tr("controls.recognize")}
-                    </button>
-                  )}
+                  {/* 识别画面按钮 */}
+                  <button
+                    className="btn--recognize"
+                    onClick={handleRecognize}
+                    disabled={isProcessing}
+                  >
+                    🔍 {tr("controls.recognize")}
+                  </button>
                   {isProcessing && (
                     <button className="btn btn--warning" onClick={interrupt}>
                       {tr("controls.interrupt")}
@@ -486,26 +445,34 @@ function AppContent() {
                     {tr("controls.stopVideo")}
                   </button>
                 </div>
-                {/* 通话态模式切换 */}
-                <div className="video-controls__mode">
-                  <button
-                    className={`mode-btn ${visionMode === "realtime" ? "mode-btn--active" : ""}`}
-                    onClick={() => setVisionMode("realtime")}
-                  >
-                    {tr("controls.mode.realtime")}
-                  </button>
-                  <button
-                    className={`mode-btn ${visionMode === "ondemand" ? "mode-btn--active" : ""}`}
-                    onClick={() => setVisionMode("ondemand")}
-                  >
-                    {tr("controls.mode.ondemand")}
-                  </button>
-                  <button
-                    className={`mode-btn ${visionMode === "chat" ? "mode-btn--active" : ""}`}
-                    onClick={() => setVisionMode("chat")}
-                  >
-                    {tr("controls.mode.chat")}
-                  </button>
+                {/* 设备选择器 */}
+                <div className="video-controls__devices">
+                  <div className="device-select-wrapper">
+                    <label className="device-select-label">📷</label>
+                    <select
+                      className="device-select"
+                      value={config.cameraDeviceId || "default"}
+                      onChange={(e) => switchDevice("camera", e.target.value === "default" ? "" : e.target.value)}
+                    >
+                      <option value="default">{tr("controls.device.default")}</option>
+                      {cameras.map((d) => (
+                        <option key={d.deviceId} value={d.deviceId}>{d.label}</option>
+                      ))}
+                    </select>
+                  </div>
+                  <div className="device-select-wrapper">
+                    <label className="device-select-label">🎤</label>
+                    <select
+                      className="device-select"
+                      value={config.micDeviceId || "default"}
+                      onChange={(e) => switchDevice("mic", e.target.value === "default" ? "" : e.target.value)}
+                    >
+                      <option value="default">{tr("controls.device.default")}</option>
+                      {mics.map((d) => (
+                        <option key={d.deviceId} value={d.deviceId}>{d.label}</option>
+                      ))}
+                    </select>
+                  </div>
                 </div>
               </>
             ) : (
@@ -547,9 +514,6 @@ function AppContent() {
                   </option>
                 ))}
               </select>
-              {isConnected && mode === "observation" && (
-                <span className="chat-panel-header__mode">{tr("chat.mode.observation")}</span>
-              )}
               {isConnected && stats.queryCount > 0 && (
                 <span className="chat-panel-header__stats">
                   {stats.queryCount} {tr("statusbar.recognitions")}

frontend/src/components/CameraManager/index.tsx

@@ -19,10 +19,13 @@ export function useCamera() {
   const [stream, setStream] = useState<MediaStream | null>(null);
   const [error, setError] = useState<string | null>(null);
 
-  const startCamera = useCallback(async () => {
+  const startCamera = useCallback(async (deviceId?: string) => {
     try {
+      const videoConstraints: MediaTrackConstraints = deviceId
+        ? { deviceId: { exact: deviceId }, width: 640, height: 480 }
+        : { facingMode: "environment", width: 640, height: 480 };
       const mediaStream = await navigator.mediaDevices.getUserMedia({
-        video: { facingMode: "environment", width: 640, height: 480 },
+        video: videoConstraints,
         audio: false,
       });
       setStream(mediaStream);

frontend/src/components/MicManager/index.tsx

@@ -12,15 +12,13 @@ export function useMicrophone() {
   const [error, setError] = useState<string | null>(null);
   const audioContextRef = useRef<AudioContext | null>(null);
 
-  const startMic = useCallback(async () => {
+  const startMic = useCallback(async (deviceId?: string) => {
     try {
+      const audioConstraints: MediaTrackConstraints = deviceId
+        ? { deviceId: { exact: deviceId }, sampleRate: 16000, channelCount: 1, echoCancellation: true, noiseSuppression: true }
+        : { sampleRate: 16000, channelCount: 1, echoCancellation: true, noiseSuppression: true };
       const mediaStream = await navigator.mediaDevices.getUserMedia({
-        audio: {
-          sampleRate: 16000,
-          channelCount: 1,
-          echoCancellation: true,
-          noiseSuppression: true,
-        },
+        audio: audioConstraints,
         video: false,
       });
       setStream(mediaStream);

frontend/src/hooks/useDeviceList.ts

@@ -0,0 +1,44 @@
+// ============================================================
+// useDeviceList — 设备枚举 Hook
+// 职责：枚举摄像头/麦克风设备列表，监听设备热插拔
+// 注意：首次枚举需要先有一次成功的 getUserMedia 授权
+// ============================================================
+
+import { useCallback, useEffect, useState } from "react";
+
+export interface DeviceInfo {
+  deviceId: string;
+  label: string;
+}
+
+export function useDeviceList() {
+  const [cameras, setCameras] = useState<DeviceInfo[]>([]);
+  const [mics, setMics] = useState<DeviceInfo[]>([]);
+
+  /** 枚举当前可用的音视频输入设备 */
+  const refreshDevices = useCallback(async () => {
+    try {
+      const devices = await navigator.mediaDevices.enumerateDevices();
+      setCameras(
+        devices
+          .filter((d) => d.kind === "videoinput")
+          .map((d) => ({ deviceId: d.deviceId, label: d.label || `摄像头 ${d.deviceId.slice(0, 4)}` }))
+      );
+      setMics(
+        devices
+          .filter((d) => d.kind === "audioinput")
+          .map((d) => ({ deviceId: d.deviceId, label: d.label || `麦克风 ${d.deviceId.slice(0, 4)}` }))
+      );
+    } catch (err) {
+      console.warn("[DeviceList] 枚举设备失败:", err);
+    }
+  }, []);
+
+  // 监听设备热插拔
+  useEffect(() => {
+    navigator.mediaDevices.addEventListener("devicechange", refreshDevices);
+    return () => navigator.mediaDevices.removeEventListener("devicechange", refreshDevices);
+  }, [refreshDevices]);
+
+  return { cameras, mics, refreshDevices };
+}

frontend/src/hooks/useObservationMode.ts

@@ -1,88 +0,0 @@
-// ============================================================
-// useObservationMode — 观察模式 Hook
-// 职责：定时采帧 → 关键帧检测 → 画面变化时触发回调
-// 来源：docs/05-用户故事.md US-05（持续场景监控）
-// ============================================================
-
-import { useCallback, useEffect, useRef, useState } from "react";
-import { sampleFrame, compareFrames } from "../components/EdgeProcessor";
-
-/** 画面变化显著阈值 */
-const CHANGE_THRESHOLD = 0.85;
-/** 采样间隔（ms） */
-const SAMPLE_INTERVAL = 5000;
-
-export interface ObservationOptions {
-  /** 画面变化回调，携带当前帧的 DataURL */
-  onChange?: (frameDataUrl: string) => void;
-}
-
-export function useObservationMode(options?: ObservationOptions) {
-  const [isObserving, setIsObserving] = useState(false);
-  const intervalRef = useRef<ReturnType<typeof setInterval> | null>(null);
-  const prevFrameRef = useRef<Uint8ClampedArray | null>(null);
-  const optionsRef = useRef(options);
-
-  useEffect(() => {
-    optionsRef.current = options;
-  }, [options]);
-
-  /**
-   * 启动观察模式
-   * @param video 摄像头 video 元素
-   * @param captureFrame 从 video 捕获 DataURL 的函数
-   */
-  const startObserving = useCallback(
-    (video: HTMLVideoElement | null, captureFrame: () => string | null) => {
-      if (!video) return;
-
-      // 立即采一帧作为基准
-      prevFrameRef.current = sampleFrame(video);
-
-      intervalRef.current = setInterval(() => {
-        const current = sampleFrame(video);
-        if (!current) return;
-
-        if (prevFrameRef.current) {
-          const { similarity } = compareFrames(prevFrameRef.current, current);
-
-          if (similarity < CHANGE_THRESHOLD) {
-            console.log(
-              `[Observation] 画面变化 (similarity=${similarity.toFixed(2)})`,
-            );
-            const frameDataUrl = captureFrame();
-            if (frameDataUrl) {
-              optionsRef.current?.onChange?.(frameDataUrl);
-            }
-          }
-        }
-
-        prevFrameRef.current = current;
-      }, SAMPLE_INTERVAL);
-
-      setIsObserving(true);
-    },
-    [],
-  );
-
-  /** 停止观察模式 */
-  const stopObserving = useCallback(() => {
-    if (intervalRef.current) {
-      clearInterval(intervalRef.current);
-      intervalRef.current = null;
-    }
-    prevFrameRef.current = null;
-    setIsObserving(false);
-  }, []);
-
-  // 组件卸载时清理
-  useEffect(() => {
-    return () => {
-      if (intervalRef.current) {
-        clearInterval(intervalRef.current);
-      }
-    };
-  }, []);
-
-  return { isObserving, startObserving, stopObserving };
-}

frontend/src/hooks/useVisionSession.ts

@@ -17,11 +17,9 @@ import { useCamera } from "../components/CameraManager";
 import { useMicrophone } from "../components/MicManager";
 import { useVAD, sampleFrame } from "../components/EdgeProcessor";
 import { useWebSocketManager } from "../components/WebSocketManager";
-import { useObservationMode } from "./useObservationMode";
+import { useDeviceList } from "./useDeviceList";
 import type { ChatMessage, SessionConfig, ServerMessage, LLMDoneMessage } from "../types";
 
-export type SessionMode = "dialogue" | "observation";
-
 export interface SessionStats {
   queryCount: number;
   totalTokens: number;
@@ -35,7 +33,6 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
   const [isAudioPlaying, setIsAudioPlaying] = useState(false);
   const [config, setConfig] = useState<SessionConfig>(loadConfig);
   const [stats, setStats] = useState<SessionStats>({ queryCount: 0, totalTokens: 0 });
-  const [mode, setMode] = useState<SessionMode>("dialogue");
   const [isCameraOn, setIsCameraOn] = useState(false);
   const [isMicOn, setIsMicOn] = useState(false);
 
@@ -59,6 +56,7 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
   const { videoRef, captureFrame, startCamera, stopCamera, stream } = useCamera();
   const { startMic, stopMic } = useMicrophone();
   const { status, connect, disconnect, send } = useWebSocketManager();
+  const { cameras, mics, refreshDevices } = useDeviceList();
 
   // 用 ref 跟踪 isProcessing，避免 VAD 回调闭包问题
   const isProcessingRef = useRef(false);
@@ -78,49 +76,6 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
     conversationIdRef.current = conversationId;
   }, [conversationId]);
 
-  // 观察模式：画面变化时自动发送 query
-  const { isObserving, startObserving, stopObserving } = useObservationMode({
-    onChange: useCallback(
-      (frameDataUrl: string) => {
-        if (isProcessingRef.current) return;
-
-        const requestId = uuidv4();
-        send({
-          type: "query",
-          request_id: requestId,
-          image: dataUrlToBase64(frameDataUrl),
-          audio: "", // 观察模式无音频
-        });
-
-        setMessages((prev) => [
-          ...prev,
-          {
-            id: uuidv4(),
-            role: "user",
-            content: t("session.changeDetected"),
-            timestamp: Date.now(),
-          },
-        ]);
-        setStats((prev) => ({ ...prev, queryCount: prev.queryCount + 1 }));
-        setIsProcessing(true);
-      },
-      [send],
-    ),
-  });
-
-  /** 切换对话/观察模式 */
-  const toggleMode = useCallback(() => {
-    setMode((prev) => {
-      const next = prev === "dialogue" ? "observation" : "dialogue";
-      if (next === "observation") {
-        startObserving(videoRef.current, captureFrame);
-      } else {
-        stopObserving();
-      }
-      return next;
-    });
-  }, [videoRef, captureFrame, startObserving, stopObserving]);
-
   // WebSocket 连接成功后发送 config + flush 待发消息
   useEffect(() => {
     if (status === "connected") {
@@ -324,14 +279,14 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
 
     // 2. 尝试获取摄像头（可选）
     try {
-      await startCamera();
+      await startCamera(config.cameraDeviceId || undefined);
       setIsCameraOn(true);
     } catch {
       console.warn("[Session] 无法获取摄像头权限，将以纯文本模式运行");
     }
 
     // 3. 尝试获取麦克风（可选）
-    const micStream = await startMic();
+    const micStream = await startMic(config.micDeviceId || undefined);
     if (micStream) {
       setIsMicOn(true);
       // 4. 启动 VAD（仅在麦克风可用时）
@@ -339,12 +294,13 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
     } else {
       console.warn("[Session] 无法获取麦克风权限，将以文本输入模式运行");
     }
-  }, [startCamera, startMic, connect, startVAD, accessToken]);
+
+    // 5. 授权后刷新设备列表
+    refreshDevices();
+  }, [startCamera, startMic, connect, startVAD, accessToken, config.cameraDeviceId, config.micDeviceId, refreshDevices]);
 
   /** 结束会话 */
   const stopSession = useCallback(async () => {
-    stopObserving();
-    setMode("dialogue");
     await stopVAD();
     stopMic();
     stopCamera();
@@ -359,12 +315,10 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
     prevFrameRef.current = null;
     setIsCameraOn(false);
     setIsMicOn(false);
-  }, [stopObserving, stopVAD, stopMic, stopCamera, disconnect]);
+  }, [stopVAD, stopMic, stopCamera, disconnect]);
 
   /** 结束视频，保留聊天和连接 */
   const stopVideo = useCallback(async () => {
-    stopObserving();
-    setMode("dialogue");
     await stopVAD();
     stopMic();
     stopCamera();
@@ -375,7 +329,7 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
     setIsCameraOn(false);
     setIsMicOn(false);
     // 不断开 WebSocket，不清空消息、统计
-  }, [stopObserving, stopVAD, stopMic, stopCamera]);
+  }, [stopVAD, stopMic, stopCamera]);
 
   /** 摄像头开关 */
   const toggleCamera = useCallback(async () => {
@@ -383,10 +337,10 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
       stopCamera();
       setIsCameraOn(false);
     } else {
-      await startCamera();
+      await startCamera(config.cameraDeviceId || undefined);
       setIsCameraOn(true);
     }
-  }, [isCameraOn, startCamera, stopCamera]);
+  }, [isCameraOn, startCamera, stopCamera, config.cameraDeviceId]);
 
   /** 麦克风开关 */
   const toggleMic = useCallback(async () => {
@@ -395,13 +349,13 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
       stopMic();
       setIsMicOn(false);
     } else {
-      const micStream = await startMic();
+      const micStream = await startMic(config.micDeviceId || undefined);
       if (micStream) {
         await startVAD(micStream);
         setIsMicOn(true);
       }
     }
-  }, [isMicOn, startMic, stopMic, startVAD, stopVAD]);
+  }, [isMicOn, startMic, stopMic, startVAD, stopVAD, config.micDeviceId]);
 
   /** 打断当前回复 */
   const interrupt = useCallback(() => {
@@ -421,6 +375,31 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
     setIsProcessing(false);
   }, [send, currentReply]);
 
+  /** 切换设备（摄像头或麦克风） */
+  const switchDevice = useCallback(async (kind: "camera" | "mic", deviceId: string) => {
+    if (kind === "camera") {
+      updateConfig({ cameraDeviceId: deviceId || undefined });
+      if (isCameraOn) {
+        stopCamera();
+        try {
+          await startCamera(deviceId || undefined);
+        } catch {
+          console.warn("[Session] 切换摄像头失败");
+        }
+      }
+    } else {
+      updateConfig({ micDeviceId: deviceId || undefined });
+      if (isMicOn) {
+        await stopVAD();
+        stopMic();
+        const micStream = await startMic(deviceId || undefined);
+        if (micStream) {
+          await startVAD(micStream);
+        }
+      }
+    }
+  }, [isCameraOn, isMicOn, stopCamera, startCamera, stopMic, startMic, stopVAD, startVAD, updateConfig]);
+
   /** 发送文本消息（手动输入） */
   const sendTextMessage = useCallback(
     (text: string) => {
@@ -480,9 +459,6 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
     config,
     updateConfig,
     stats,
-    mode,
-    isObserving,
-    toggleMode,
     startSession,
     stopSession,
     stopVideo,
@@ -493,5 +469,8 @@ export function useVisionSession(accessToken?: string | null, conversationId?: s
     toggleMic,
     sendTextMessage,
     captureFrame,
+    cameras,
+    mics,
+    switchDevice,
   };
 }

frontend/src/lib/i18n/en-US.ts

@@ -48,7 +48,6 @@ export const enUS: TranslationMap = {
   "scenario.interpreter.hint": "AI will translate your speech in real-time (Chinese-English), without explanations",
 
   // Video indicators
-  "video.observing": "👁️ Observing",
   "video.listening": "🎤 Listening...",
   "video.playing": "🔊 Playing...",
   "video.initVad": "Initializing voice detection...",
@@ -67,8 +66,6 @@ export const enUS: TranslationMap = {
   "controls.cameraOn": "Turn on camera",
   "controls.micOff": "Turn off microphone",
   "controls.micOn": "Turn on microphone",
-  "controls.observing": "👁️ Observing",
-  "controls.observation": "👁️ Observe",
   "controls.interrupt": "⏹ Interrupt",
   "controls.stop": "End Session",
   "controls.stopVideo": "End Video",
@@ -77,7 +74,6 @@ export const enUS: TranslationMap = {
 
   // Chat panel
   "chat.title": "Chat",
-  "chat.mode.observation": "Observing",
   "chat.reconnecting": "Connection lost, reconnecting...",
   "chat.connecting": "Connecting to server...",
   "chat.vadInit": "Initializing voice detection...",
@@ -91,7 +87,6 @@ export const enUS: TranslationMap = {
   "chat.scenarioSwitched": "Switched to {name} mode",
 
   // Session messages
-  "session.changeDetected": "👁️ Scene change detected",
   "session.recognizing": "(Recognizing speech...)",
   "session.sttFailed": "(Speech recognition failed, please try again)",
   "session.noSpeech": "(No speech detected)",
@@ -138,12 +133,7 @@ export const enUS: TranslationMap = {
 
   // Video controls (enhanced)
   "controls.recognize": "Analyze Scene",
-  "controls.device.camera": "Camera",
-  "controls.device.mic": "Microphone",
   "controls.device.default": "Default",
-  "controls.mode.realtime": "Realtime",
-  "controls.mode.ondemand": "On-demand",
-  "controls.mode.chat": "Chat only",
 
   // Status bar
   "statusbar.ready": "Ready · Select devices to start",

frontend/src/lib/i18n/ja-JP.ts

@@ -48,7 +48,6 @@ export const jaJP: TranslationMap = {
   "scenario.interpreter.hint": "AIがあなたの発言をリアルタイムで翻訳します（中日相互翻訳、説明なし）",
 
   // Video indicators
-  "video.observing": "👁️ 観察中",
   "video.listening": "🎤 聞き取り中...",
   "video.playing": "🔊 再生中...",
   "video.initVad": "音声検出を初期化中...",
@@ -67,8 +66,6 @@ export const jaJP: TranslationMap = {
   "controls.cameraOn": "カメラをオン",
   "controls.micOff": "マイクをオフ",
   "controls.micOn": "マイクをオン",
-  "controls.observing": "👁️ 観察中",
-  "controls.observation": "👁️ 観察モード",
   "controls.interrupt": "⏹ 中断",
   "controls.stop": "対話を終了",
   "controls.stopVideo": "ビデオ終了",
@@ -77,7 +74,6 @@ export const jaJP: TranslationMap = {
 
   // Chat panel
   "chat.title": "チャット",
-  "chat.mode.observation": "観察モード",
   "chat.reconnecting": "接続が切断されました。再接続中...",
   "chat.connecting": "サーバーに接続中...",
   "chat.vadInit": "音声検出を初期化中...",
@@ -91,7 +87,6 @@ export const jaJP: TranslationMap = {
   "chat.scenarioSwitched": "{name} モードに切り替えました",
 
   // Session messages
-  "session.changeDetected": "👁️ シーン変化を検出",
   "session.recognizing": "（音声認識中...）",
   "session.sttFailed": "（音声認識に失敗しました。もう一度お試しください）",
   "session.noSpeech": "（音声が検出されませんでした）",
@@ -138,12 +133,7 @@ export const jaJP: TranslationMap = {
 
   // Video controls (enhanced)
   "controls.recognize": "シーンを分析",
-  "controls.device.camera": "カメラ",
-  "controls.device.mic": "マイク",
   "controls.device.default": "デフォルト",
-  "controls.mode.realtime": "リアルタイム",
-  "controls.mode.ondemand": "オンデマンド",
-  "controls.mode.chat": "チャットのみ",
 
   // Status bar
   "statusbar.ready": "準備完了 · デバイスを選択して開始",

frontend/src/lib/i18n/zh-CN.ts

@@ -48,7 +48,6 @@ export const zhCN: TranslationMap = {
   "scenario.interpreter.hint": "AI 会实时翻译你的话（中英互译），无解释评论",
 
   // Video indicators
-  "video.observing": "👁️ 观察中",
   "video.listening": "🎤 正在聆听...",
   "video.playing": "🔊 正在播放...",
   "video.initVad": "正在初始化语音检测...",
@@ -67,8 +66,6 @@ export const zhCN: TranslationMap = {
   "controls.cameraOn": "开启摄像头",
   "controls.micOff": "关闭麦克风",
   "controls.micOn": "开启麦克风",
-  "controls.observing": "👁️ 观察中",
-  "controls.observation": "👁️ 观察模式",
   "controls.interrupt": "⏹ 打断",
   "controls.stop": "结束对话",
   "controls.stopVideo": "结束视频",
@@ -77,7 +74,6 @@ export const zhCN: TranslationMap = {
 
   // Chat panel
   "chat.title": "对话",
-  "chat.mode.observation": "观察模式",
   "chat.reconnecting": "连接已断开，正在重连...",
   "chat.connecting": "正在连接服务...",
   "chat.vadInit": "正在初始化语音检测...",
@@ -91,7 +87,6 @@ export const zhCN: TranslationMap = {
   "chat.scenarioSwitched": "已切换到 {name} 模式",
 
   // Session messages
-  "session.changeDetected": "👁️ 画面变化检测",
   "session.recognizing": "（语音识别中...）",
   "session.sttFailed": "（语音识别失败，请重试）",
   "session.noSpeech": "（未识别到语音）",
@@ -138,12 +133,7 @@ export const zhCN: TranslationMap = {
 
   // Video controls (enhanced)
   "controls.recognize": "识别画面",
-  "controls.device.camera": "摄像头",
-  "controls.device.mic": "麦克风",
   "controls.device.default": "默认",
-  "controls.mode.realtime": "实时分析",
-  "controls.mode.ondemand": "按需识别",
-  "controls.mode.chat": "纯聊天",
 
   // Status bar
   "statusbar.ready": "就绪 · 选择设备后开始通话",

frontend/src/types/index.ts

@@ -10,6 +10,8 @@ export interface SessionConfig {
   detailLevel: "low" | "high";
   language: string;
   scenario: string;    // 情景 ID，如 "free_chat"、"interviewer"
+  cameraDeviceId?: string;  // 摄像头设备 ID，空 = 系统默认
+  micDeviceId?: string;     // 麦克风设备 ID，空 = 系统默认
 }
 
 export type Theme = "dark" | "light";