fix(desktop): translate the AI chat error title and default chat titles

The error bubble in AI chat always said "Error occurred", and a chat
without a title was named "<date> chat" or "<date> timeline summary" with
the date in the UI language but the rest in English. Both now come from
the locale files.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/layer/renderer/src/modules/ai-chat/components/message/ErrorMessage.tsx

@@ -1,8 +1,8 @@
 import { Spring } from "@follow/components/constants/spring.js"
 import { cn } from "@follow/utils"
-import { ExceptionCodeMap } from "@follow-app/client-sdk"
 import { m } from "motion/react"
 import * as React from "react"
+import { useTranslation } from "react-i18next"
 
 import { getErrorMessage, parseAIError } from "~/modules/ai-chat/utils/error"
 
@@ -17,6 +17,7 @@ interface ErrorMessageProps {
  * Note: Rate limit errors are handled separately by RateLimitNotice component
  */
 export const ErrorMessage: React.FC<ErrorMessageProps> = ({ error, className }) => {
+  const { t } = useTranslation("ai")
   const parsedError = React.useMemo(() => parseAIError(error), [error])
 
   if (parsedError.isRateLimitError) {
@@ -36,20 +37,6 @@ export const ErrorMessage: React.FC<ErrorMessageProps> = ({ error, className })
     }
   }
 
-  const getErrorTitle = () => {
-    if (parsedError.isBusinessError) {
-      switch (errorCode) {
-        case ExceptionCodeMap.AIRateLimitExceeded: {
-          return "AI Rate Limit Exceeded"
-        }
-        default: {
-          return "Error occurred"
-        }
-      }
-    }
-    return "Error occurred"
-  }
-
   const contextualInfo = getContextualInfo()
 
   return (
@@ -66,7 +53,9 @@ export const ErrorMessage: React.FC<ErrorMessageProps> = ({ error, className })
             {/* Header with subtle icon */}
             <div className="flex items-center gap-2">
               <i className="i-mgc-information-cute-re size-4 text-text-tertiary" />
-              <span className="text-xs font-medium text-text-secondary">{getErrorTitle()}</span>
+              <span className="text-xs font-medium text-text-secondary">
+                {t("chat.error.occurred")}
+              </span>
             </div>
 
             {/* Error message - always visible but subtle */}

apps/desktop/layer/renderer/src/modules/ai-chat/services/index.ts

@@ -266,7 +266,7 @@ class AIPersistServiceStatic {
       const referenceDate = timestamps?.updatedAt ?? timestamps?.createdAt ?? new Date()
       const formattedDateTime = this.formatDateTime(referenceDate, i18n.language)
 
-      return `${formattedDateTime} chat`
+      return i18n.t("chat.default_title.chat", { ns: "ai", time: formattedDateTime })
     }
 
     const datePart = chatId.slice(prefix.length)
@@ -287,7 +287,7 @@ class AIPersistServiceStatic {
 
     const formattedDateTime = this.formatDateTime(targetDate, i18n.language)
 
-    return `${formattedDateTime} timeline summary`
+    return i18n.t("chat.default_title.timeline_summary", { ns: "ai", time: formattedDateTime })
   }
 
   private formatDateTime(date: Date, locale?: string): string {

locales/ai/en.json

@@ -55,7 +55,10 @@
   "chat.context.additional": "Additional Context",
   "chat.context.unread_only": "Unread Only",
   "chat.context.upload_files": "Upload Files",
+  "chat.default_title.chat": "{{time}} chat",
+  "chat.default_title.timeline_summary": "{{time}} timeline summary",
   "chat.error.description": "Don't worry! You can try again or reload the chat to continue your conversation.",
+  "chat.error.occurred": "Error occurred",
   "chat.error.reload_page": "Reload Page",
   "chat.error.stream_timeout": "The reply stopped arriving, so it was ended. Retry your message to try again.",
   "chat.error.title": "AI Chat Encountered an Error",

locales/ai/fr-FR.json

@@ -55,7 +55,10 @@
   "chat.context.additional": "Contexte supplémentaire",
   "chat.context.unread_only": "Non lus uniquement",
   "chat.context.upload_files": "Importer des fichiers",
+  "chat.default_title.chat": "Discussion du {{time}}",
+  "chat.default_title.timeline_summary": "Résumé de la chronologie du {{time}}",
   "chat.error.description": "Pas d'inquiétude ! Vous pouvez réessayer ou recharger la discussion pour poursuivre votre conversation.",
+  "chat.error.occurred": "Une erreur s'est produite",
   "chat.error.reload_page": "Recharger la page",
   "chat.error.stream_timeout": "La réponse a cessé d'arriver et a été interrompue. Réessayez votre message.",
   "chat.error.title": "La discussion IA a rencontré une erreur",

locales/ai/ja.json

@@ -55,7 +55,10 @@
   "chat.context.additional": "その他のコンテキスト",
   "chat.context.unread_only": "未読のみ",
   "chat.context.upload_files": "ファイルをアップロード",
+  "chat.default_title.chat": "{{time}} のチャット",
+  "chat.default_title.timeline_summary": "{{time}} のタイムラインの要約",
   "chat.error.description": "ご安心ください。再試行するか、チャットを再読み込みすると会話を続けられます。",
+  "chat.error.occurred": "エラーが発生しました",
   "chat.error.reload_page": "ページを再読み込み",
   "chat.error.stream_timeout": "応答が途中で届かなくなったため終了しました。メッセージを再試行してください。",
   "chat.error.title": "AI チャットでエラーが発生しました",

locales/ai/zh-CN.json

@@ -55,7 +55,10 @@
   "chat.context.additional": "其他上下文",
   "chat.context.unread_only": "仅未读",
   "chat.context.upload_files": "上传文件",
+  "chat.default_title.chat": "{{time}} 对话",
+  "chat.default_title.timeline_summary": "{{time}} 时间线摘要",
   "chat.error.description": "别担心！您可以重试或重新加载对话，继续之前的交流。",
+  "chat.error.occurred": "出错了",
   "chat.error.reload_page": "重新加载页面",
   "chat.error.stream_timeout": "回复长时间没有新内容，已结束。请重试你的消息。",
   "chat.error.title": "AI 对话出错了",

locales/ai/zh-TW.json

@@ -55,7 +55,10 @@
   "chat.context.additional": "其他上下文",
   "chat.context.unread_only": "僅未讀",
   "chat.context.upload_files": "上傳檔案",
+  "chat.default_title.chat": "{{time}} 對話",
+  "chat.default_title.timeline_summary": "{{time}} 時間軸摘要",
   "chat.error.description": "別擔心！您可以重試或重新載入對話，繼續先前的交流。",
+  "chat.error.occurred": "發生錯誤",
   "chat.error.reload_page": "重新載入頁面",
   "chat.error.stream_timeout": "回覆長時間沒有新內容，已結束。請重試你的訊息。",
   "chat.error.title": "AI 對話發生錯誤",