feat(admin): live redis kill-switch on tunnel actions, sortable columns + CSV export + bulk actions, Node 24 LTS

WS1: pin all Docker stages to node:24.16.0-alpine; add engines node>=20.
WS2: lib/redis.ts gains TTL-backed redisSet, redisDel, setTunnelActive (writes tunnel:active:<sub>=1/0 EX 30, TUNNEL_ACTIVE_TTL override, no-op without REDIS_URL); wired into tunnel active/delete/reassign routes.
WS3: sortable columns, CSV export routes (token excluded), and bulk actions (self-account guard) across users/tunnels/audit admin tables.

app/api/admin/audit/export/route.ts

@@ -0,0 +1,73 @@
+import { type NextRequest, NextResponse } from 'next/server';
+import { requireAdminApi } from '@/lib/auth/admin-guard';
+import { getAuditList } from '@/lib/admin/list';
+import { logAdminAction } from '@/lib/auth/audit';
+import { toCsv, EXPORT_MAX_ROWS } from '@/lib/admin/csv';
+
+export const runtime = 'nodejs';
+export const dynamic = 'force-dynamic';
+
+export async function GET(req: NextRequest) {
+  const auth = await requireAdminApi();
+  if (!auth.ok) return auth.response;
+
+  const url = new URL(req.url);
+  const action = url.searchParams.get('action') ?? '';
+  const targetType = url.searchParams.get('target_type') ?? '';
+  const sort = url.searchParams.get('sort');
+  const order = url.searchParams.get('order');
+
+  try {
+    // Respect action/target_type filters + sort, full set (capped). Audit
+    // details already exclude secrets (no tokens are ever logged).
+    const { entries } = await getAuditList({
+      page: 1,
+      perPage: EXPORT_MAX_ROWS,
+      action,
+      targetType,
+      sort,
+      order,
+    });
+
+    const header = [
+      'created_at',
+      'actor_email',
+      'action',
+      'target_type',
+      'target_id',
+      'details',
+    ];
+    const rows = entries.map((e) => [
+      e.created_at,
+      e.actor_email ?? '',
+      e.action,
+      e.target_type ?? '',
+      e.target_id ?? '',
+      JSON.stringify(e.details ?? {}),
+    ]);
+
+    const csv = toCsv(header, rows);
+
+    await logAdminAction(auth.user, {
+      action: 'audit.export',
+      target_type: 'audit',
+      details: { count: rows.length, capped: rows.length >= EXPORT_MAX_ROWS },
+    });
+
+    return new NextResponse(csv, {
+      status: 200,
+      headers: {
+        'Content-Type': 'text/csv; charset=utf-8',
+        'Content-Disposition': 'attachment; filename="audit.csv"',
+        'Cache-Control': 'no-store',
+        Pragma: 'no-cache',
+      },
+    });
+  } catch (e) {
+    console.error('admin audit export failed', e);
+    return NextResponse.json(
+      { error: 'internal error' },
+      { status: 500, headers: { 'Cache-Control': 'no-store' } },
+    );
+  }
+}

app/api/admin/audit/route.ts

@@ -16,6 +16,8 @@ export async function GET(req: NextRequest) {
   const perPage = parsePerPageParam(url.searchParams.get('perPage'), 50, 100);
   const action = url.searchParams.get('action') ?? '';
   const targetType = url.searchParams.get('target_type') ?? '';
+  const sort = url.searchParams.get('sort');
+  const order = url.searchParams.get('order');
 
   try {
     const { entries, total } = await getAuditList({
@@ -23,6 +25,8 @@ export async function GET(req: NextRequest) {
       perPage,
       action,
       targetType,
+      sort,
+      order,
     });
     return jsonNoStore({ entries, total, page, perPage });
   } catch (e) {