docs: update link note copy in all locale lang files

修正并更新了多语言版本里的链接提示文案，将原有的"链接和二维码"调整为"课程识别码"，补充了每日重新生成的说明

src/lang/cn.json

@@ -910,5 +910,5 @@
   "ssLongTimeNoOperation": "长时间无操作，将自动退出",
   "ssConfirmExit": "确认退出登录嘛？",
   "ssDownloadQRCode": "下载二维码",
-  "ssLinkNote": "注:该链接以及二维码仅当天有效！"
+  "ssLinkNote": "注:课程识别码仅当天有效，每日重新生成"
 }

src/lang/en.json

@@ -910,5 +910,5 @@
   "ssLongTimeNoOperation": "Long time no operation, will be logged out",
   "ssConfirmExit": "Are you sure you want to exit login?",
   "ssDownloadQRCode": "Download QR Code",
-  "ssLinkNote": "Note: This link and QR code are only valid for the day!"
+  "ssLinkNote": "Note: Course identification code is only valid for the day, regenerated daily."
 }

src/lang/hk.json

@@ -910,5 +910,5 @@
   "ssLongTimeNoOperation": "長時間無操作，將自動退出",
   "ssConfirmExit": "確認退出登錄嘛？",
   "ssDownloadQRCode": "下載二維碼",
-  "ssLinkNote": "注:該鏈接以及二維碼僅當天有效！"
+  "ssLinkNote": "註:課程識別碼僅當天有效，每日重新生成"
 }