fix(i18n): replace raw translation keys on panel screens (#7057)

Use valid translation keys on six panel screens, add the missing copy-failure and empty-value strings across all locales, and reject unresolved literal translation keys in the regression test.

internal/web/translation/fa-IR.json

@@ -40,6 +40,7 @@
   "indefinite": "نامحدود",
   "unlimited": "نامحدود",
   "none": "هیچ",
+  "empty": "خالی",
   "qrCode": "QRکد",
   "info": "اطلاعات بیشتر",
   "edit": "ویرایش",
@@ -47,6 +48,7 @@
   "reset": "بازنشانی",
   "noData": "داده‌ای وجود ندارد.",
   "copySuccess": "باموفقیت کپی‌شد",
+  "copyFail": "کپی ناموفق بود",
   "sure": "مطمئن",
   "encryption": "رمزگذاری",
   "transmission": "راه‌اتصال",