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/css/style.css

@@ -289,6 +289,7 @@ body {
 .fc-red    { color: #dc2626; }
 .fc-neutral { color: #6b7280; }
 .fc-blue   { color: #2563eb; }
+.fc-dark   { color: #374151; }
 
 /* ── Log viewer (dark theme — keep as-is) ────────── */
 .log-viewer {