fix: use full doc.id as fallback order_number to avoid unique constraint collision

backend/migration/migrate_crm_orders.py

@@ -90,7 +90,7 @@ async def run() -> None:
             skipped += 1
             continue
 
-        order_number = d.get("order_number") or f"ORD-LEGACY-{doc.id[:8]}"
+        order_number = d.get("order_number") or f"ORD-LEGACY-{doc.id}"
 
         created_at = _coerce_dt(d.get("created_at")) or _now_utc()
         updated_at = _coerce_dt(d.get("updated_at")) or _now_utc()