feat(sync): handle cancelled GoMag orders (status Anulata / statusId 7)

- Add web_status column to orders table (generic name for platform status)
- Filter cancelled orders during sync, record as CANCELLED in SQLite
- Soft-delete previously-imported cancelled orders in Oracle (if not invoiced)
- Add CANCELLED filter pill + badge in dashboard UI
- New soft_delete_order_in_roa() and mark_order_cancelled() functions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/app/static/js/shared.js

@@ -219,6 +219,9 @@ function statusDot(status) {
         case 'ERROR':
         case 'FAILED':
             return '<span class="dot dot-red"></span>';
+        case 'CANCELLED':
+        case 'DELETED_IN_ROA':
+            return '<span class="dot dot-gray"></span>';
         default:
             return '<span class="dot dot-gray"></span>';
     }