fix: delete expired email on read path to ensure 24h retention

src/index.js

@@ -64,6 +64,10 @@ export default {
     if (!row) return json(null);
 
     if (Date.now() - row.received_at > ONE_DAY_MS) {
+      // 读取时发现过期，立即删除，避免库里长期残留
+      await env.DB.prepare(
+        `DELETE FROM latest_emails WHERE recipient = ? AND received_at = ?`
+      ).bind(row.recipient, row.received_at).run();
       return json(null);
     }