fix: surface backend error details in proxy toast messages

The takeover.failed i18n template lacked the {{detail}} placeholder
and three useProxyStatus onError callbacks omitted the detail variable,
so proxy start/stop/takeover failures all displayed a generic message
regardless of the underlying cause.

src/components/SubscriptionQuotaFooter.tsx

@@ -205,7 +205,9 @@ export const SubscriptionQuotaView: React.FC<SubscriptionQuotaViewProps> = ({
   }
 
   // 成功获取数据
-  const tiers = (quota.tiers || []).filter((tier) => tier.name in TIER_I18N_KEYS);
+  const tiers = (quota.tiers || []).filter(
+    (tier) => tier.name in TIER_I18N_KEYS,
+  );
   if (tiers.length === 0) return null;
 
   // ── inline 模式：紧凑两行显示 ──