Add invitation frontend: invite modal, pending invitations, no-company view

Members Index:
- "Invite Member" button opens InviteMemberModal (email + role dropdown)
- Pending invitations section shows below members table with cancel buttons
- Members store gains inviteMember, fetchPendingInvitations, cancelInvitation

CompanySwitcher:
- Shows pending invitations greyed out below active companies
- Each with Accept/Decline mini-buttons
- Accepting refreshes bootstrap and switches to new company

NoCompanyView:
- Standalone page for users with zero accepted companies
- Shows pending invitations with Accept/Decline or "no companies" message
- Route: /admin/no-company

Invitation Pinia store:
- Manages user's own pending invitations (fetchPending, accept, decline)
- Bootstrap populates invitations from API response

Global store:
- Bootstrap action stores pending_invitations from response

resources/scripts/admin/admin-router.js

@@ -136,7 +136,16 @@ const AdminUpdateApp = () =>
 const AdminFileDisk = () =>
   import('@/scripts/admin/views/settings/FileDiskSetting.vue')
 
+const NoCompanyView = () =>
+  import('@/scripts/admin/views/NoCompanyView.vue')
+
 export default [
+  {
+    path: '/admin/no-company',
+    name: 'no.company',
+    component: NoCompanyView,
+    meta: { requiresAuth: true },
+  },
   {
     path: '/installation',
     component: LayoutInstallation,