fix: 优化公开聊天页登录态恢复与鉴权引导

- 支持复用现有登录态并恢复 refresh token

- 未认证访问时补充跳转登录提示与引导文案

easyflow-ui-admin/app/src/locales/langs/en-US/bot.json

@@ -50,6 +50,8 @@
   "embedUsageTip2": "Embed only in trusted sites and combine with rate limiting.",
   "publicPageBlocked": "Anonymous access is disabled for this bot",
   "publicPageBlockedTip": "Enable anonymous access in publish settings before using external links.",
+  "publicPageLoginRequired": "Authentication required",
+  "publicPageLoginRequiredTip": "This chat page requires a valid login session or access token before it can be used.",
   "publicChatTitle": "Public Chat Assistant",
   "publicChatSubtitle": "Powered by EasyFlow",
   "publicChatPlaceholder": "Type your question and press Enter to send",

easyflow-ui-admin/app/src/locales/langs/zh-CN/bot.json

@@ -50,6 +50,8 @@
   "embedUsageTip2": "建议仅在可信站点嵌入，并结合限流策略使用。",
   "publicPageBlocked": "该助手未开放匿名访问",
   "publicPageBlockedTip": "请在发布设置中开启“允许匿名访问”后再通过外链访问。",
+  "publicPageLoginRequired": "用户未认证，请登录",
+  "publicPageLoginRequiredTip": "当前聊天页需要有效登录态或访问令牌后才可继续使用。",
   "publicChatTitle": "公开聊天助手",
   "publicChatSubtitle": "由 EasyFlow 驱动",
   "publicChatPlaceholder": "输入你的问题，按 Enter 发送",