fix(firstleg): finalize loading before customs acceptance

firstleg/src/test/java/com/baiyue/firstleg/service/SmartLoadingServiceTest.java

@@ -41,6 +41,7 @@ import java.util.List;
 import java.util.Map;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.assertj.core.api.Assertions.catchThrowableOfType;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
@@ -595,6 +596,23 @@ class SmartLoadingServiceTest {
         assertThat(updated.getValue().getWarehouseRemark()).isEqualTo("装柜时注意外箱");
     }
 
+    @Test
+    void pickedQuantityConflictPrecedesCandidateAvailabilityValidation() {
+        LoadingPlanEntity plan = plan("LOADING", 2);
+        LoadingPlanItemEntity line = item(8, 9, 20, 2);
+        when(repository.plan(1L)).thenReturn(plan);
+        when(repository.item(1L, 8L)).thenReturn(line);
+        when(loadingPickService.mutationSnapshot(1L)).thenReturn(
+            new LoadingPickService.MutationSnapshot(77L, "LOADING", 6, Map.of(8L, 2)));
+
+        assertThatThrownBy(() -> service.adjust(1L, 8L,
+            new AdjustRequest(1, 2, 0, "adjust-picked"), 7L, "u"))
+            .hasMessageContaining("不能低于已拣货箱数");
+
+        verify(repository, never()).candidate(anyLong(), anyLong(), anyLong());
+        verify(repository, never()).touch(anyLong(), anyInt(), anyLong(), anyString());
+    }
+
     @Test
     void preservesDownstreamCode() {
         stubAssignment();