feat: agency portfolio with per-client integrations hub

Admin home lists tenants, alerts, and connection health; header
selector enables superadmin context; Meta/GA4/GSC/GTM/CRM/email
slots live per tenant (manual status until OAuth).

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/dashboard/page.tsx

@@ -1,5 +1,14 @@
 import { redirect } from 'next/navigation';
+import { createClient } from '@/lib/supabase/server';
+import { isAgencyRole, userRole } from '@/lib/agency';
 
-export default function DashboardIndex() {
+export default async function DashboardIndex() {
+  const supabase = await createClient();
+  const {
+    data: { user },
+  } = await supabase.auth.getUser();
+  if (user && isAgencyRole(userRole(user))) {
+    redirect('/dashboard/agencia');
+  }
   redirect('/dashboard/kpis');
 }