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/lib/api.ts

@@ -51,7 +51,7 @@ import type {
   UiMcpServerDescriptor,
   WsEvent,
 } from '@/types';
-import { getCurrentAppLocale, pickAppText } from '@/lib/i18n/core';
+import { getCurrentAppLocale, pickAppText, type AppLocale } from '@/lib/i18n/core';
 
 const API_URL = process.env.NEXT_PUBLIC_API_URL?.trim();
 const WS_URL = process.env.NEXT_PUBLIC_WS_URL?.trim();
@@ -62,6 +62,15 @@ const REQUEST_TIMEOUT_MS = 8000;
 const OUTLOOK_REQUEST_TIMEOUT_MS = 45000;
 const SKILL_LEARNING_REQUEST_TIMEOUT_MS = 120000;
 
+export type PromptLocale = 'zh-Hans' | 'zh-Hant' | 'en';
+
+export function promptLocaleForAppLocale(locale: AppLocale): PromptLocale {
+  if (locale === 'zh-Hant') {
+    return 'zh-Hant';
+  }
+  return locale === 'en-US' ? 'en' : 'zh-Hans';
+}
+
 function isBrowser(): boolean {
   return typeof window !== 'undefined';
 }
@@ -271,6 +280,7 @@ export async function sendMessage(
     replyToScheduledRunId?: string;
     scheduledReplyIntent?: 'revise_once' | 'update_future' | 'continue_task';
     thinkingEnabled?: boolean;
+    promptLocale?: PromptLocale;
   }
 ): Promise<{
   response?: string;
@@ -281,7 +291,11 @@ export async function sendMessage(
   task_status?: string | null;
   evidence_status?: string | null;
 }> {
-  const body: Record<string, unknown> = { message, session_id: sessionId };
+  const body: Record<string, unknown> = {
+    message,
+    session_id: sessionId,
+    prompt_locale: options?.promptLocale || promptLocaleForAppLocale(getCurrentAppLocale()),
+  };
   if (attachments && attachments.length > 0) {
     body.attachments = attachments;
   }
@@ -356,7 +370,11 @@ export function streamMessage(
       const res = await fetch(buildApiUrl('/api/chat/stream'), {
         method: 'POST',
         headers: authHeaders(),
-        body: JSON.stringify({ message, session_id: sessionId }),
+        body: JSON.stringify({
+          message,
+          session_id: sessionId,
+          prompt_locale: promptLocaleForAppLocale(getCurrentAppLocale()),
+        }),
         signal: controller.signal,
       });