chore: Assets 디렉토리 구조 정리 및 네이밍 컨벤션 적용

- Assets/_Game/ 하위로 게임 에셋 통합
- External/ 패키지 벤더별 분류 (Synty, Animations, UI)
- 에셋 네이밍 컨벤션 확립 및 적용
  (Data_Skill_, Data_SkillEffect_, Prefab_, Anim_, Model_, BT_ 등)
- pre-commit hook으로 네이밍 컨벤션 자동 검사 추가
- RESTRUCTURE_CHECKLIST.md 작성

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Assets/External/TextMesh Pro/Examples & Extras/Scripts/TMP_PhoneNumberValidator.cs

@@ -0,0 +1,105 @@
+using UnityEngine;
+using System.Collections;
+using System;
+
+namespace TMPro
+{
+    /// <summary>
+    /// Example of a Custom Character Input Validator to only allow phone number in the (800) 555-1212 format.
+    /// </summary>
+    [Serializable]
+    //[CreateAssetMenu(fileName = "InputValidator - Phone Numbers.asset", menuName = "TextMeshPro/Input Validators/Phone Numbers")]
+    public class TMP_PhoneNumberValidator : TMP_InputValidator
+    {
+        // Custom text input validation function
+        public override char Validate(ref string text, ref int pos, char ch)
+        {
+            Debug.Log("Trying to validate...");
+            
+            // Return unless the character is a valid digit
+            if (ch < '0' && ch > '9') return (char)0;
+
+            int length = text.Length;
+
+            // Enforce Phone Number format for every character input.
+            for (int i = 0; i < length + 1; i++)
+            {
+                switch (i)
+                {
+                    case 0:
+                        if (i == length)
+                            text = "(" + ch;
+                        pos = 2;
+                        break;
+                    case 1:
+                        if (i == length)
+                            text += ch;
+                        pos = 2;
+                        break;
+                    case 2:
+                        if (i == length)
+                            text += ch;
+                        pos = 3;
+                        break;
+                    case 3:
+                        if (i == length)
+                            text += ch + ") ";
+                        pos = 6;
+                        break;
+                    case 4:
+                        if (i == length)
+                            text += ") " + ch;
+                        pos = 7;
+                        break;
+                    case 5:
+                        if (i == length)
+                            text += " " + ch;
+                        pos = 7;
+                        break;
+                    case 6:
+                        if (i == length)
+                            text += ch;
+                        pos = 7;
+                        break;
+                    case 7:
+                        if (i == length)
+                            text += ch;
+                        pos = 8;
+                        break;
+                    case 8:
+                        if (i == length)
+                            text += ch + "-";
+                        pos = 10;
+                        break;
+                    case 9:
+                        if (i == length)
+                            text += "-" + ch;
+                        pos = 11;
+                        break;
+                    case 10:
+                        if (i == length)
+                            text += ch;
+                        pos = 11;
+                        break;
+                    case 11:
+                        if (i == length)
+                            text += ch;
+                        pos = 12;
+                        break;
+                    case 12:
+                        if (i == length)
+                            text += ch;
+                        pos = 13;
+                        break;
+                    case 13:
+                        if (i == length)
+                            text += ch;
+                        pos = 14;
+                        break;
+                }
+            }
+
+            return ch;
+        }
+    }
+}