Add Super Admin login routing and wire tenant onboarding to auto-create a location

super_admin is now a real LoginRole, derived from the server's
issuperadmin flag (not a client-guessable roleid) — routes exclusively
to a new minimal SuperAdminPage, never the merchant console.

That page reuses the existing tenant/store/rider onboarding wizard
(AdminConsole) rather than duplicating it — its Tenant tab was already
calling the right composite endpoint but had nowhere to send location
data, and was never actually reachable from anywhere in the app. Now
it collects a primary outlet name + business category and sends a
nested tenantlocations object, so one submit provisions tenant +
active location + admin user instead of leaving the tenant
locationless. createTenantUser also moves off the mob API base onto
the web one, matching where this is actually called from.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/components/SuperAdminPage.tsx

@@ -0,0 +1,45 @@
+/**
+ * @license
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * Exclusive landing page for issuperadmin logins — a platform operator, not
+ * scoped to any tenant. Deliberately minimal: no sidebar, no merchant nav,
+ * just the shared Header (for logout) and the existing tenant/store/rider
+ * onboarding wizard (AdminConsole), which until now was only reachable
+ * scoped to a single tenant's own Settings page.
+ */
+
+import React from 'react';
+import { Routes, Route, Navigate } from 'react-router-dom';
+import Header from './Header';
+import AdminConsole from './AdminConsole';
+import type { AuthUser } from '../services/auth';
+
+interface SuperAdminPageProps {
+  user: AuthUser;
+  onLogout: () => void;
+}
+
+export default function SuperAdminPage({ user, onLogout }: SuperAdminPageProps) {
+  const profile = { name: user.name, role: 'Super Admin', email: user.email };
+
+  return (
+    <div className="min-h-screen bg-slate-50 flex flex-col">
+      <Header
+        isSidebarOpen={false}
+        onToggleSidebar={() => {}}
+        onHelpClick={() => {}}
+        onLogoutClick={onLogout}
+        profile={profile}
+      />
+      <main className="flex-1 p-4 md:p-6">
+        <Routes>
+          <Route path="onboarding" element={<AdminConsole showHeader />} />
+          <Route path="*" element={<Navigate to="onboarding" replace />} />
+        </Routes>
+      </main>
+    </div>
+  );
+}