feat：添加对话情景功能

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

@@ -26,6 +26,21 @@ export const zhCN: TranslationMap = {
   "settings.detail.high": "高",
   "settings.language": "语言",
   "settings.language.desc": "交互语言偏好",
+  "settings.scenario": "对话情景",
+  "settings.scenario.desc": "选择 AI 扮演的角色",
+
+  // Scenarios
+  "scenario.choose": "选择对话情景",
+  "scenario.freeChat": "自由对话",
+  "scenario.freeChat.desc": "AI 视觉助手，自由聊天",
+  "scenario.interviewer": "模拟面试官",
+  "scenario.interviewer.desc": "AI 扮演面试官，进行模拟面试",
+  "scenario.englishTeacher": "英语老师",
+  "scenario.englishTeacher.desc": "AI 英语外教，纠正语法并引导对话",
+  "scenario.debate": "辩论对手",
+  "scenario.debate.desc": "AI 反驳你的观点，锻炼逻辑思维",
+  "scenario.interpreter": "同声翻译",
+  "scenario.interpreter.desc": "实时中英互译，口语化翻译",
 
   // Video indicators
   "video.observing": "👁️ 观察中",
@@ -63,6 +78,7 @@ export const zhCN: TranslationMap = {
   "chat.userLabel": "你",
   "chat.input.placeholder": "输入文字对话...",
   "chat.send": "发送",
+  "chat.scenarioSwitched": "已切换到 {name} 模式",
 
   // Session messages
   "session.changeDetected": "👁️ 画面变化检测",