Add frontend handling for users without a company

Make setSelectedCompany null-safe and clear stale localStorage.
Conditionally initialize company store state in bootstrap. Add
router guard to redirect no-company users to NoCompanyView while
allowing super admins through. Hide sidebar when no company.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

resources/scripts/admin/admin-router.js

@@ -147,12 +147,6 @@ export default [
     component: RegisterWithInvitation,
     meta: { requiresAuth: false },
   },
-  {
-    path: '/admin/no-company',
-    name: 'no.company',
-    component: NoCompanyView,
-    meta: { requiresAuth: true },
-  },
   {
     path: '/installation',
     component: LayoutInstallation,
@@ -203,6 +197,11 @@ export default [
     component: LayoutBasic,
     meta: { requiresAuth: true },
     children: [
+      {
+        path: 'no-company',
+        name: 'no.company',
+        component: NoCompanyView,
+      },
       {
         path: 'dashboard',
         name: 'dashboard',