feat(settings): schedule picker, toggle placement, sub-theme docs link

- Replace the Telegram "Notification Time" free-text field with a guided
  cron builder: @every + number + unit (s/m/h), the @hourly/@daily/@weekly/
  @monthly macros, and a Custom option that seeds a valid 6-field crontab
  (cron runs with seconds enabled) as an escape hatch.
- Move "Restart Xray After Auto Disable" from the External Traffic tab to
  Panel Settings, where it belongs.
- Add a "Template guide" link to the Sub Theme Directory setting pointing at
  docs/custom-subscription-templates.md.
- Localize all new strings across every locale.

internal/web/translation/en-US.json

@@ -1006,7 +1006,18 @@
       "telegramChatId": "Admin Chat ID",
       "telegramChatIdDesc": "The Telegram Admin Chat ID(s). (comma-separated)(get it here {'@'}userinfobot) or (use '/id' command in the bot)",
       "telegramNotifyTime": "Notification Time",
-      "telegramNotifyTimeDesc": "The Telegram bot notification time set for periodic reports. (use the crontab time format)",
+      "telegramNotifyTimeDesc": "How often the Telegram bot sends periodic reports. Pick a preset interval, or choose Custom to enter a raw crontab expression.",
+      "notifyTime": {
+        "every": "@every — repeat at an interval",
+        "hourly": "@hourly — every hour",
+        "daily": "@daily — every day at 00:00",
+        "weekly": "@weekly — every week",
+        "monthly": "@monthly — every month",
+        "custom": "Custom (crontab)",
+        "seconds": "Seconds",
+        "minutes": "Minutes",
+        "hours": "Hours"
+      },
       "tgNotifyBackup": "Database Backup",
       "tgNotifyBackupDesc": "Send a database backup file with a report.",
       "tgNotifyLogin": "Login Notification",
@@ -1037,6 +1048,7 @@
       "subAnnounceDesc": "The announcement text displayed in the VPN client",
       "subThemeDir": "Sub Theme Directory",
       "subThemeDirDesc": "Absolute path to a folder containing a custom index.html/sub.html subscription page template (e.g. /etc/3x-ui/sub_templates/my-theme/). Leave empty to use the default page.",
+      "subThemeDirDocs": "Template guide ↗",
       "subEnableRouting": "Enable routing",
       "subEnableRoutingDesc": "Global setting to enable routing in the VPN client. (Only for Happ)",
       "subRoutingRules": "Routing rules",