feat: Implement S2A account cleaner management and a global application configuration context, with supporting backend API.

frontend/src/pages/Cleaner.tsx

@@ -108,6 +108,30 @@ export default function Cleaner() {
         }
     }
 
+    // 计算下次清理时间
+    const getNextCleanTime = (): string => {
+        if (!cleanEnabled) return '未启用'
+        if (!status?.last_clean_time || status.last_clean_time === '0001-01-01T00:00:00Z') {
+            return '即将执行'
+        }
+        try {
+            const lastTime = new Date(status.last_clean_time)
+            const nextTime = new Date(lastTime.getTime() + cleanInterval * 1000)
+            // 如果下次时间已过，说明即将执行
+            if (nextTime <= new Date()) {
+                return '即将执行'
+            }
+            return nextTime.toLocaleString('zh-CN', {
+                month: '2-digit',
+                day: '2-digit',
+                hour: '2-digit',
+                minute: '2-digit'
+            })
+        } catch {
+            return '未知'
+        }
+    }
+
     if (loading) {
         return (
             <div className="flex items-center justify-center h-64">
@@ -193,6 +217,9 @@ export default function Cleaner() {
                                 <p className="text-2xl font-bold text-slate-900 dark:text-slate-100">
                                     {formatInterval(cleanInterval)}
                                 </p>
+                                <p className="text-xs text-slate-400 dark:text-slate-500 mt-1">
+                                    下次清理: {getNextCleanTime()}
+                                </p>
                             </div>
                             <div className="h-12 w-12 rounded-xl bg-blue-100 dark:bg-blue-900/30 flex items-center justify-center">
                                 <Clock className="h-6 w-6 text-blue-500" />