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/hooks/useInvitations.ts

@@ -8,7 +8,7 @@ import apiClient from '../api/client';
 export interface StaffInvitation {
   id: number;
   email: string;
-  role: 'TENANT_MANAGER' | 'TENANT_STAFF';
+  role: 'TENANT_STAFF';
   role_display: string;
   status: 'PENDING' | 'ACCEPTED' | 'DECLINED' | 'EXPIRED' | 'CANCELLED';
   invited_by: number | null;
@@ -50,7 +50,7 @@ export interface StaffPermissions {
 
 export interface CreateInvitationData {
   email: string;
-  role: 'TENANT_MANAGER' | 'TENANT_STAFF';
+  role: 'TENANT_STAFF';
   create_bookable_resource?: boolean;
   resource_name?: string;
   permissions?: StaffPermissions;