修复无法兑换bug

apps/backend/src/utils/time.ts

@@ -6,3 +6,18 @@ export function addHours(baseIso: string | null | undefined, hours: number): str
   const baseTime = baseIso ? new Date(baseIso).getTime() : Date.now()
   return new Date(baseTime + hours * 60 * 60 * 1000).toISOString()
 }
+
+export function normalizeTimestampIso(value: unknown, fallbackIso = nowIso()): string {
+  if (value instanceof Date) {
+    const timestamp = value.getTime()
+    return Number.isFinite(timestamp) ? value.toISOString() : fallbackIso
+  }
+
+  const normalized = String(value || '').trim()
+  if (!normalized) {
+    return fallbackIso
+  }
+
+  const timestamp = Date.parse(normalized)
+  return Number.isFinite(timestamp) ? new Date(timestamp).toISOString() : fallbackIso
+}