fix: merchant-users page shows role from user.role instead of owned_merchants_count

The Role column was deriving Owner/Team Member from owned_merchants_count
which was unreliable. Now uses user.role directly (merchant_owner vs
store_member) which is the source of truth after RBAC Phase 1.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/tenancy/templates/tenancy/admin/merchant-users.html

@@ -167,10 +167,10 @@
                         <!-- Role -->
                         <td class="px-4 py-3 text-xs">
                             <span class="px-2 py-1 font-semibold leading-tight rounded-full"
-                                  :class="user.owned_merchants_count > 0
+                                  :class="user.role === 'merchant_owner'
                                       ? 'text-orange-700 bg-orange-100 dark:bg-orange-700 dark:text-orange-100'
                                       : 'text-blue-700 bg-blue-100 dark:bg-blue-700 dark:text-blue-100'"
-                                  x-text="user.owned_merchants_count > 0 ? 'Owner' : 'Team Member'">
+                                  x-text="user.role === 'merchant_owner' ? 'Merchant Owner' : 'Store Member'">
                             </span>
                         </td>