fix: 密钥管理排除站点列表缺少无账号站点

loadExclusionSources() 原只从 accounts 提取站点，
新增的/无关联账号的站点不显示。
增加 api.getSites() 调用，合并所有站点到排除选项。

src/web/pages/DownstreamKeys.tsx

@@ -518,17 +518,29 @@ export default function DownstreamKeys() {
     if (exclusionSourceLoading || exclusionSourceLoaded) return;
     setExclusionSourceLoading(true);
     try {
-      const [accountsSnapshotRes, tokensRes] = await Promise.all([
+      const [accountsSnapshotRes, tokensRes, sitesRes] = await Promise.all([
         api.getAccountsSnapshot(),
         api.getAccountTokens(),
+        api.getSites(),
       ]);
 
       const accountRows = Array.isArray(accountsSnapshotRes?.accounts)
         ? accountsSnapshotRes.accounts
         : [];
       const tokenRows = Array.isArray(tokensRes) ? tokensRes : [];
+      const siteRows = Array.isArray(sitesRes) ? sitesRes : [];
 
       const siteMap = new Map<number, { siteId: number; siteName: string; accountIds: Set<number> }>();
+
+      for (const site of siteRows) {
+        const siteId = Number(site?.id);
+        if (!Number.isFinite(siteId) || siteId <= 0) continue;
+        const siteName = String(site?.name || `站点 ${siteId}`).trim() || `站点 ${siteId}`;
+        if (!siteMap.has(siteId)) {
+          siteMap.set(siteId, { siteId, siteName, accountIds: new Set<number>() });
+        }
+      }
+
       for (const account of accountRows) {
         const siteId = Number(account?.site?.id);
         const accountId = Number(account?.id);