- Add Username row (@handle) to Account information section in AccountView.vue
- Add Handle column (th + td with @prefix) to users table in AdminUsersTab.vue
- Both use existing data already present in API responses (no backend changes)
- Export adminDeleteUser(id, adminPassword) from client.js — sends JSON body to DELETE /api/admin/users/{id}
- AdminUsersTab: add confirmDelete, deletePassword, deleteError state refs
- AdminUsersTab: add startDelete, cancelDelete, confirmDoDelete functions (mutually exclusive with deactivate panel)
- AdminUsersTab: Delete button added to active and deactivated user rows
- AdminUsersTab: inline password confirmation panel with Argon2 verification via backend