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/zh-TW.json

@@ -1005,7 +1005,18 @@
       "telegramChatId": "管理員聊天 ID",
       "telegramChatIdDesc": "Telegram 管理員聊天 ID (多個以逗號分隔)（可通過 {'@'}userinfobot 獲取，或在機器人中使用 '/id' 命令獲取）",
       "telegramNotifyTime": "通知時間",
-      "telegramNotifyTimeDesc": "設定週期性的 Telegram 機器人通知時間（使用 crontab 時間格式）",
+      "telegramNotifyTimeDesc": "Telegram 機器人傳送週期性報告的頻率。選擇預設間隔，或選擇「自訂」以輸入 crontab 運算式。",
+      "notifyTime": {
+        "every": "@every — 依間隔重複",
+        "hourly": "@hourly — 每小時",
+        "daily": "@daily — 每天 00:00",
+        "weekly": "@weekly — 每週",
+        "monthly": "@monthly — 每月",
+        "custom": "自訂 (crontab)",
+        "seconds": "秒",
+        "minutes": "分鐘",
+        "hours": "小時"
+      },
       "tgNotifyBackup": "資料庫備份",
       "tgNotifyBackupDesc": "傳送帶有報告的資料庫備份檔案",
       "tgNotifyLogin": "登入通知",
@@ -1036,6 +1047,7 @@
       "subAnnounceDesc": "VPN 用戶端中顯示的公告文字",
       "subThemeDir": "訂閱主題目錄",
       "subThemeDirDesc": "包含自訂訂閱頁面範本 (index.html/sub.html) 的資料夾的絕對路徑（例如 /etc/3x-ui/sub_templates/my-theme/）。留空則使用預設頁面。",
+      "subThemeDirDocs": "範本指南 ↗",
       "subEnableRouting": "啟用路由",
       "subEnableRoutingDesc": "在 VPN 用戶端中啟用路由的全域設定。（僅限 Happ）",
       "subRoutingRules": "路由規則",