fix: use ancestor chain check for pick item matching terminal object

- PickItemFromPoint returns leaf geometry, not the parent container
- Check if pickItem is terminalObject or its descendant via AncestorsAndSelf

src/UI/WPF/ViewModels/PathEditingViewModel.cs

@@ -2527,10 +2527,23 @@ namespace NavisworksTransport.UI.WPF.ViewModels
             // 恢复选择工具
             try { NavisApplication.MainDocument.Tool.Value = Tool.Select; } catch { }
 
-            if (!result.IsValid || result.ModelItem != _assemblyTerminalObject)
+            if (!result.IsValid)
+            {
+                CleanupAssemblyEndFaceSelection(clearVisuals: false);
+                UpdateMainStatus("取面失败: 未命中有效面。");
+                return;
+            }
+
+            // PickItemFromPoint 返回的是底层几何节点，需要沿父链检查是否属于终点箱体
+            var pickItem = result.ModelItem;
+            var matched = pickItem != null && (
+                pickItem == _assemblyTerminalObject ||
+                pickItem.AncestorsAndSelf.Any(a => a == _assemblyTerminalObject));
+            if (!matched)
             {
                 CleanupAssemblyEndFaceSelection(clearVisuals: false);
                 UpdateMainStatus("取面失败: 请确认点击的是终点箱体的端面。");
+                LogManager.Debug($"[直线装配] 取面命中 {ModelItemAnalysisHelper.GetSafeDisplayName(pickItem)}, 非终点箱体");
                 return;
             }