✨ chore: Improve subscription billing fallback and UI states

Add a lightweight active-subscription check to skip subscription pre-consume when none exist, reducing unnecessary transactions and locks. In the subscription UI, disable subscription-first options when no active plan is available, show the effective fallback to wallet with a clear notice, and distinguish “invalidated” from “expired” states. Update i18n strings across supported locales to reflect the new messages and status labels.

web/src/i18n/locales/ja.json

@@ -2675,10 +2675,13 @@
     "我的订阅": "私のサブスクリプション",
     "个生效中": "件有効中",
     "无生效": "有効なし",
+    "已保存偏好为": "保存された設定は",
+    "，当前无生效订阅，将自动使用钱包": "、有効なサブスクリプションがないため、自動的にウォレットを使用します",
     "个已过期": "件期限切れ",
     "订阅": "サブスクリプション",
     "至": "まで",
     "过期于": "有効期限",
+    "作废于": "無効化日",
     "购买套餐后即可享受模型权益": "プラン購入後にモデル特典を利用できます",
     "限购": "購入制限",
     "推荐": "おすすめ",