refactor(api): 统一 HTTP 200 响应契约

warehouse/src/test/java/com/baiyue/warehouse/controller/WarehouseDataAccessExceptionHandlerTest.java

@@ -13,7 +13,7 @@ import static org.mockito.Mockito.when;
 @DisplayName("仓库数据访问异常处理器")
 class WarehouseDataAccessExceptionHandlerTest {
     @Test
-    @DisplayName("数据源故障统一返回503并保留请求标识")
+    @DisplayName("数据源故障统一返回HTTP 200与S0503业务码并保留请求标识")
     void shouldReturnServiceUnavailableAndPreserveRequestIdsForDataSourceFailure() {
         HttpServletRequest request = mock(HttpServletRequest.class);
         when(request.getAttribute("requestId")).thenReturn("request-1");
@@ -22,7 +22,7 @@ class WarehouseDataAccessExceptionHandlerTest {
         var response = new WarehouseDataAccessExceptionHandler().handle(
             new DataAccessResourceFailureException("database unavailable"), request);
 
-        assertThat(response.getStatusCode().value()).isEqualTo(503);
+        assertThat(response.getStatusCode().value()).isEqualTo(200);
         assertThat(response.getBody()).isNotNull();
         assertThat(response.getBody().code()).isEqualTo(ResultCode.SERVICE_UNAVAILABLE.code());
         assertThat(response.getBody().message()).contains("数据库");