fix: add out_of_stock to stock XML; remove invalid date_add order filter

- PrestashopClient.toStockAvailableXml: add out_of_stock=2 (use shop
  default) — PS 8.2.5 returns 400 code 41 without this field
- PrestashopClient.getOrdersSince: remove filter[date_add] — PS 8.2.5
  does not expose date_add as a filterable field for orders (400 code 32)
  Re-import prevention handled by OrderMapping.existsByPrestashopOrderId

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

sync-service/src/main/java/com/teterialosjuanjos/tfg/sync_service/integration/prestashop/PrestashopClient.java

@@ -10,7 +10,6 @@ import org.springframework.web.client.RestClient;
 
 import java.nio.charset.StandardCharsets;
 import java.time.LocalDateTime;
-import java.time.format.DateTimeFormatter;
 import java.util.List;
 import java.util.Optional;
 
@@ -28,9 +27,6 @@ import java.util.Optional;
 @Component
 public class PrestashopClient {
 
-    private static final DateTimeFormatter PS_DATE_FORMAT =
-            DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
-
     private final RestClient restClient;
     private final String wsKey;
 
@@ -167,20 +163,19 @@ public class PrestashopClient {
     // ── Orders ────────────────────────────────────────────────────────────
 
     /**
-     * Returns orders created on or after {@code since}, with full details and order rows.
+     * Returns all orders with full details and order rows.
      *
-     * <p>PrestaShop date filter syntax: {@code filter[date_add]=[>=yyyy-MM-dd HH:mm:ss]}</p>
+     * <p>PS 8.2.5 does not expose {@code date_add} as a filterable field for orders.
+     * Re-import prevention is handled by {@code OrderMapping} in the service layer.</p>
      *
-     * @param since lower bound (inclusive) for {@code date_add}
+     * @param since unused — kept for API compatibility; deduplication is done via OrderMapping
      */
     public List<PrestashopOrderDto> getOrdersSince(LocalDateTime since) {
-        String dateFilter = "[>=%s]".formatted(since.format(PS_DATE_FORMAT));
         PrestashopOrderDto.ListResponse response = restClient.get()
                 .uri(u -> u.path("/orders")
                         .queryParam("ws_key", wsKey)
                         .queryParam("output_format", "JSON")
                         .queryParam("display", "full")
-                        .queryParam("filter[date_add]", dateFilter)
                         .build())
                 .retrieve()
                 .body(PrestashopOrderDto.ListResponse.class);
@@ -258,6 +253,7 @@ public class PrestashopClient {
         sb.append("<id_product_attribute>").append(idAttr).append("</id_product_attribute>");
         sb.append("<quantity>").append(dto.quantity()).append("</quantity>");
         sb.append("<depends_on_stock>0</depends_on_stock>");
+        sb.append("<out_of_stock>2</out_of_stock>");
         sb.append("</stock_available>");
         sb.append("</prestashop>");
         return sb.toString();