fix(admin): eliminate GoTrue empty-body 500s under bulk load (retry-all + undici keep-alive + sequential bulk), CSV formula-injection guard

app/admin/page.tsx

@@ -1,6 +1,7 @@
 import Link from 'next/link';
 import { computeMetrics } from '@/lib/admin/metrics';
 import { getSupabaseAdmin } from '@/lib/supabase/admin';
+import { withAdminRetry } from '@/lib/admin/retry';
 import { formatBytes, formatDate } from '@/lib/format';
 
 export const dynamic = 'force-dynamic';
@@ -18,10 +19,12 @@ export default async function AdminOverviewPage() {
   const admin = getSupabaseAdmin();
 
   // Recent signups (latest 5 users).
-  const { data: recentUsersData } = await admin.auth.admin.listUsers({
-    page: 1,
-    perPage: 5,
-  });
+  const { data: recentUsersData } = await withAdminRetry(() =>
+    admin.auth.admin.listUsers({
+      page: 1,
+      perPage: 5,
+    }),
+  );
   const recentUsers = recentUsersData?.users ?? [];
 
   // Over-quota tunnels (compute in memory).

app/admin/tunnels/tunnels-table.tsx

@@ -237,6 +237,11 @@ export function TunnelsTable({
       } catch {
         result.fail++;
       }
+      // Tiny inter-op pacing: strictly sequential (concurrency 1) with a small
+      // gap so we never burst the admin API; single refresh after all settle.
+      if (i < targets.length - 1) {
+        await new Promise((r) => setTimeout(r, 75));
+      }
     }
     setBulkProgress(null);
     setBulkBusy(false);

app/admin/users/users-table.tsx

@@ -136,6 +136,12 @@ export function UsersTable({
       } catch {
         result.fail++;
       }
+      // Tiny inter-op pacing: keep the per-row mutations strictly sequential
+      // (concurrency 1) with a small gap so we never burst the GoTrue admin
+      // API, then refresh ONCE after every op has settled (below).
+      if (i < targets.length - 1) {
+        await new Promise((r) => setTimeout(r, 75));
+      }
     }
     setBulkProgress(null);
     setBulkBusy(false);