feat: 支持多语言提示词本地化和界面优化

- 添加 prompt_locale 参数支持简体中文、繁体中文和英文提示词本地化
- 移除内置 agents 配置以简化系统架构
- 更新 ContextBuilder 使用动态提示词模板而非硬编码内容
- 在 AgentLoop、Web 接口和 AgentService 中传递 locale 参数
- 添加输出语言指令确保用户界面内容按指定语言生成
- 扩展前端 LanguageSwitcher 组件支持三种语言选项
- 优化 Header 和侧边栏组件的响应式布局和文本截断处理
- 更新测试用例验证不同语言环境下的提示词正确性

app-instance/frontend/app/(app)/page.tsx

@@ -23,6 +23,7 @@ import {
   getSession,
   getSessionProcess,
   listSessions,
+  promptLocaleForAppLocale,
   sendMessage,
   submitChatFeedback,
   uploadFile,
@@ -44,7 +45,7 @@ function isSessionUpdatedEvent(data: WsEvent | Record<string, unknown>): data is
   return data.type === 'session_updated' && typeof data.session_id === 'string';
 }
 
-function activeTaskStatusLabel(status: string, locale: 'zh-CN' | 'en-US') {
+function activeTaskStatusLabel(status: string, locale: string) {
   if (status === 'needs_revision') return pickAppText(locale, '待修改', 'Needs revision');
   if (status === 'awaiting_acceptance') return pickAppText(locale, '待验收', 'Awaiting acceptance');
   if (status === 'running') return pickAppText(locale, '进行中', 'Running');
@@ -140,8 +141,9 @@ export default function ChatPage() {
         liveRuns: processRuns,
         liveEvents: processEvents,
         liveArtifacts: processArtifacts,
+        locale,
       }),
-    [activeTaskDetail, processArtifacts, processEvents, processRuns]
+    [activeTaskDetail, locale, processArtifacts, processEvents, processRuns]
   );
 
   const loadSessions = useCallback(async () => {
@@ -400,6 +402,7 @@ export default function ChatPage() {
         type: 'message',
         content: msgContent,
         thinking_enabled: thinkingModeEnabled,
+        prompt_locale: promptLocaleForAppLocale(locale),
       };
       if (attachments.length > 0) {
         wsPayload.attachments = attachments;