feat: add single-point+normal overload to AssemblyEndFaceAnalyzer

- New Analyze(triangles, hitPoint, normal) bypasses 3-point seed plane construction
- New Analyze(modelItem, hitPoint, normal) for Navisworks types
- Same triangle extraction and centroid computation as 3-point version
- Enables single-click end face detection via FaceInferToolPlugin

src/Utils/Assembly/AssemblyEndFaceAnalyzer.cs

@@ -128,6 +128,108 @@ namespace NavisworksTransport.Utils.GeometryAnalysis
                 $"端面识别完成: 三角形={candidateTriangles.Count}, 顶点={candidatePoints.Count}, 偏差={maxPlaneDeviation:F6}");
         }
 
+        /// <summary>
+        /// 单点+法向量分析端面。用于取面工具得到法向量后替代手工三点拾取。
+        /// </summary>
+        /// <param name="triangles">模型三角面片</param>
+        /// <param name="hitPoint">命中点</param>
+        /// <param name="normal">面法向量（需归一化）</param>
+        public static EndFaceAnalysisResult Analyze(
+            IEnumerable<AnalysisTriangle3> triangles,
+            Vector3 hitPoint,
+            Vector3 normal)
+        {
+            if (triangles == null)
+                throw new ArgumentNullException(nameof(triangles));
+
+            if (normal.LengthSquared() < 1e-12f)
+                return EndFaceAnalysisResult.Failure("法向量长度过小。");
+
+            var triangleList = triangles.ToList();
+            if (triangleList.Count == 0)
+                return EndFaceAnalysisResult.Failure("没有可用的三角几何数据。");
+
+            var seedPlane = new PlaneDefinition(Vector3.Normalize(normal), Vector3.Dot(normal, hitPoint));
+
+            var candidateTriangles = new List<AnalysisTriangle3>();
+            var candidatePoints = new HashSet<Vector3>(new Vector3EqualityComparer());
+            double maxPlaneDeviation = 0.0;
+
+            foreach (var triangle in triangleList)
+            {
+                if (!TryGetTriangleNormal(triangle, out Vector3 triangleNormal))
+                    continue;
+
+                if (Math.Abs(Vector3.Dot(triangleNormal, seedPlane.Normal)) < NormalAlignmentCosineThreshold)
+                    continue;
+
+                double d1 = Math.Abs(GetSignedDistanceToPlane(seedPlane, triangle.Point1));
+                double d2 = Math.Abs(GetSignedDistanceToPlane(seedPlane, triangle.Point2));
+                double d3 = Math.Abs(GetSignedDistanceToPlane(seedPlane, triangle.Point3));
+                double triangleDeviation = Math.Max(d1, Math.Max(d2, d3));
+                if (triangleDeviation > PlaneDistanceTolerance)
+                    continue;
+
+                candidateTriangles.Add(triangle);
+                candidatePoints.Add(ProjectPointToPlane(seedPlane, triangle.Point1));
+                candidatePoints.Add(ProjectPointToPlane(seedPlane, triangle.Point2));
+                candidatePoints.Add(ProjectPointToPlane(seedPlane, triangle.Point3));
+                maxPlaneDeviation = Math.Max(maxPlaneDeviation, triangleDeviation);
+            }
+
+            if (candidateTriangles.Count == 0 || candidatePoints.Count < 3)
+                return EndFaceAnalysisResult.Failure("没有识别到足够的端面共面三角形。");
+
+            PlaneDefinition refinedPlane = RefinePlane(seedPlane, candidatePoints);
+            PlaneBasis planeBasis = CreatePlaneBasis(refinedPlane);
+
+            double minU = double.MaxValue;
+            double maxU = double.MinValue;
+            double minV = double.MaxValue;
+            double maxV = double.MinValue;
+
+            foreach (Vector3 candidatePoint in candidatePoints)
+            {
+                Vector2 projected = ProjectToPlane2D(candidatePoint, planeBasis);
+                minU = Math.Min(minU, projected.X);
+                maxU = Math.Max(maxU, projected.X);
+                minV = Math.Min(minV, projected.Y);
+                maxV = Math.Max(maxV, projected.Y);
+            }
+
+            double extentU = maxU - minU;
+            double extentV = maxV - minV;
+            if (extentU < MinimumProjectedExtent || extentV < MinimumProjectedExtent)
+            {
+                return EndFaceAnalysisResult.Failure("识别到的端面分布过窄，无法稳定求中心。");
+            }
+
+            Vector3 center = ProjectFromPlane2D((minU + maxU) / 2.0, (minV + maxV) / 2.0, planeBasis);
+
+            return EndFaceAnalysisResult.Success(
+                center,
+                refinedPlane.Normal,
+                candidateTriangles.Count,
+                candidatePoints.Count,
+                maxPlaneDeviation,
+                $"端面识别完成（单点法向）: 三角形={candidateTriangles.Count}, 顶点={candidatePoints.Count}, 偏差={maxPlaneDeviation:F6}");
+        }
+
+        /// <summary>
+        /// 单点+法向量分析端面的 Navisworks 兼容重载。
+        /// </summary>
+        public static EndFaceAnalysisResult Analyze(ModelItem modelItem, Point3D hitPoint, Vector3D normal)
+        {
+            if (modelItem == null)
+                throw new ArgumentNullException(nameof(modelItem));
+
+            var triangles = GeometryHelper.ExtractTriangles(new[] { modelItem })
+                .Select(ConvertTriangle)
+                .ToList();
+
+            return Analyze(triangles, ToVector3(hitPoint), new Vector3((float)normal.X, (float)normal.Y, (float)normal.Z));
+        }
+
         public static Point3D ToPoint3D(Vector3 point)
         {
             return new Point3D(point.X, point.Y, point.Z);