Improve staff management UI and add sorting functionality

- Remove WIP badge from staff sidebar navigation
- Make action buttons consistent between Customers and Staff pages
  - Edit button: icon + text with gray border
  - Masquerade button: icon + text with indigo border
  - Verify email button: icon-only with colored border (green/amber)
- Add sortable columns to Staff list (name and role)
- Include migrations for tenant manager role removal

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/pages/Messages.tsx

@@ -251,7 +251,6 @@ const Messages: React.FC = () => {
   // Computed
   const roleOptions = [
     { value: 'owner', label: 'Owners', icon: Users, description: 'Business owners' },
-    { value: 'manager', label: 'Managers', icon: Users, description: 'Team leads' },
     { value: 'staff', label: 'Staff', icon: Users, description: 'Employees' },
     { value: 'customer', label: 'Customers', icon: Users, description: 'Clients' },
   ];