Refactor PrestashopClient to enhance header configuration and improve query parameter encoding

api/src/main/java/fr/gameovergne/api/service/PrestashopClient.java

@@ -30,7 +30,17 @@ public class PrestashopClient {
                 .encodeToString((apiKey + ":").getBytes(StandardCharsets.UTF_8));
 
         this.client = RestClient.builder()
-                .defaultHeader(HttpHeaders.AUTHORIZATION, "Basic " + basicAuth)
+                .baseUrl(baseUrl)
+                .defaultHeaders(headers -> {
+                    // Authentification PrestaShop via Basic Auth : key en user, mdp vide
+                    headers.setBasicAuth(apiKey, "");
+
+                    // IMPORTANT : User-Agent “neutre”
+                    headers.set(HttpHeaders.USER_AGENT, "curl/8.10.1");
+
+                    // Accept JSON
+                    headers.setAccept(List.of(MediaType.APPLICATION_JSON, MediaType.ALL));
+                })
                 .build();
 
         log.info("[PrestaShop] Base URL = {}", baseUrl);
@@ -58,8 +68,10 @@ public class PrestashopClient {
                 if (values == null || values.isEmpty()) continue;
 
                 for (String rawValue : values) {
-                    if (first) { sb.append('?'); first = false; }
-                    else sb.append('&');
+                    if (first) {
+                        sb.append('?');
+                        first = false;
+                    } else sb.append('&');
 
                     // encode la clé
                     sb.append(URLEncoder.encode(key, StandardCharsets.UTF_8));