Add optional expiration that starts on first config use.

Co-authored-by: Cursor <cursoragent@cursor.com>

translations/en.json

@@ -141,6 +141,13 @@
   "email_label": "Email (opt.)",
   "traffic_limit_label": "Traffic limit (GB) (opt., 0 = ∞)",
   "expiration_date_label": "Expiration date",
+  "no_expiration": "No expiry",
+  "expire_after_first_use": "Start after first use",
+  "expire_after_first_use_hint": "The day countdown starts when the user first gets a config (panel, share, or Telegram).",
+  "expire_days_required": "Enter a number of days greater than 0",
+  "expire_pending_label": "{} days after first use",
+  "expire_started_suffix": "countdown started",
+  "expire_already_started_hint": "Countdown already started. Valid until: {}. Uncheck to set a fixed date.",
   "description_label": "Description (opt.)",
   "auto_conn_title": "Automatic connection creation (optional)",
   "server_label": "Server",