feat: 방향전환 경로 검증 시스템 구현

- PathValidationResult 클래스를 Validation 폴더에 적절히 배치
- BacktrackingPattern 클래스로 A→B→A 패턴 상세 검출
- DirectionChangePlanner에서 되돌아가기 패턴 자동 검증
- CLAUDE.md에 AGVNavigationCore 프로젝트 구조 가이드 추가
- 빌드 시스템 오류 모두 해결

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Cs_HMI/AGVNavigationCore/PathFinding/Validation/PathValidationResult.cs

@@ -0,0 +1,205 @@
+using System.Collections.Generic;
+using AGVNavigationCore.Models;
+
+namespace AGVNavigationCore.PathFinding.Validation
+{
+    /// <summary>
+    /// 경로 검증 결과 (되돌아가기 패턴 검증 포함)
+    /// </summary>
+    public class PathValidationResult
+    {
+        /// <summary>
+        /// 경로 검증이 필요한지 여부
+        /// </summary>
+        public bool IsValidationRequired { get; set; }
+
+        /// <summary>
+        /// 경로 검증 통과 여부
+        /// </summary>
+        public bool IsValid { get; set; }
+
+        /// <summary>
+        /// 검증된 경로
+        /// </summary>
+        public List<string> ValidatedPath { get; set; }
+
+        /// <summary>
+        /// 검출된 되돌아가기 패턴 목록 (A → B → A 형태)
+        /// </summary>
+        public List<BacktrackingPattern> BacktrackingPatterns { get; set; }
+
+        /// <summary>
+        /// 갈림길 노드 목록
+        /// </summary>
+        public List<string> JunctionNodes { get; set; }
+
+        /// <summary>
+        /// 시작 노드 ID
+        /// </summary>
+        public string StartNodeId { get; set; }
+
+        /// <summary>
+        /// 목표 노드 ID
+        /// </summary>
+        public string TargetNodeId { get; set; }
+
+        /// <summary>
+        /// 갈림길 노드 ID (방향 전환용)
+        /// </summary>
+        public string JunctionNodeId { get; set; }
+
+        /// <summary>
+        /// 검증 오류 메시지 (실패시)
+        /// </summary>
+        public string ValidationError { get; set; }
+
+        /// <summary>
+        /// 기본 생성자
+        /// </summary>
+        public PathValidationResult()
+        {
+            IsValidationRequired = false;
+            IsValid = true;
+            ValidatedPath = new List<string>();
+            BacktrackingPatterns = new List<BacktrackingPattern>();
+            JunctionNodes = new List<string>();
+            StartNodeId = string.Empty;
+            TargetNodeId = string.Empty;
+            JunctionNodeId = string.Empty;
+            ValidationError = string.Empty;
+        }
+
+        /// <summary>
+        /// 검증 불필요한 경우 생성
+        /// </summary>
+        public static PathValidationResult CreateNotRequired()
+        {
+            return new PathValidationResult
+            {
+                IsValidationRequired = false,
+                IsValid = true
+            };
+        }
+
+        /// <summary>
+        /// 검증 성공 결과 생성
+        /// </summary>
+        public static PathValidationResult CreateValid(List<string> path, string startNodeId, string targetNodeId, string junctionNodeId = "")
+        {
+            return new PathValidationResult
+            {
+                IsValidationRequired = true,
+                IsValid = true,
+                ValidatedPath = new List<string>(path),
+                StartNodeId = startNodeId,
+                TargetNodeId = targetNodeId,
+                JunctionNodeId = junctionNodeId
+            };
+        }
+
+        /// <summary>
+        /// 검증 실패 결과 생성 (되돌아가기 패턴 검출)
+        /// </summary>
+        public static PathValidationResult CreateInvalidWithBacktracking(
+            List<string> path,
+            List<BacktrackingPattern> backtrackingPatterns,
+            string startNodeId,
+            string targetNodeId,
+            string junctionNodeId,
+            string error)
+        {
+            return new PathValidationResult
+            {
+                IsValidationRequired = true,
+                IsValid = false,
+                ValidatedPath = new List<string>(path),
+                BacktrackingPatterns = new List<BacktrackingPattern>(backtrackingPatterns),
+                StartNodeId = startNodeId,
+                TargetNodeId = targetNodeId,
+                JunctionNodeId = junctionNodeId,
+                ValidationError = error
+            };
+        }
+
+        /// <summary>
+        /// 일반 검증 실패 결과 생성
+        /// </summary>
+        public static PathValidationResult CreateInvalid(string startNodeId, string targetNodeId, string error)
+        {
+            return new PathValidationResult
+            {
+                IsValidationRequired = true,
+                IsValid = false,
+                StartNodeId = startNodeId,
+                TargetNodeId = targetNodeId,
+                ValidationError = error
+            };
+        }
+    }
+
+    /// <summary>
+    /// 되돌아가기 패턴 정보 (A → B → A)
+    /// </summary>
+    public class BacktrackingPattern
+    {
+        /// <summary>
+        /// 시작 노드 (A)
+        /// </summary>
+        public string StartNode { get; set; }
+
+        /// <summary>
+        /// 중간 노드 (B)
+        /// </summary>
+        public string MiddleNode { get; set; }
+
+        /// <summary>
+        /// 되돌아간 노드 (다시 A)
+        /// </summary>
+        public string ReturnNode { get; set; }
+
+        /// <summary>
+        /// 경로에서의 시작 인덱스
+        /// </summary>
+        public int StartIndex { get; set; }
+
+        /// <summary>
+        /// 경로에서의 종료 인덱스
+        /// </summary>
+        public int EndIndex { get; set; }
+
+        /// <summary>
+        /// 기본 생성자
+        /// </summary>
+        public BacktrackingPattern()
+        {
+            StartNode = string.Empty;
+            MiddleNode = string.Empty;
+            ReturnNode = string.Empty;
+            StartIndex = -1;
+            EndIndex = -1;
+        }
+
+        /// <summary>
+        /// 되돌아가기 패턴 생성
+        /// </summary>
+        public static BacktrackingPattern Create(string startNode, string middleNode, string returnNode, int startIndex, int endIndex)
+        {
+            return new BacktrackingPattern
+            {
+                StartNode = startNode,
+                MiddleNode = middleNode,
+                ReturnNode = returnNode,
+                StartIndex = startIndex,
+                EndIndex = endIndex
+            };
+        }
+
+        /// <summary>
+        /// 패턴 설명 문자열
+        /// </summary>
+        public override string ToString()
+        {
+            return $"{StartNode} → {MiddleNode} → {ReturnNode} (인덱스: {StartIndex}-{EndIndex})";
+        }
+    }
+}