feat(identity): add entity identity registry and archive listing

Assets/Scripts/Archive/IdentityListUI.cs

@@ -0,0 +1,83 @@
+using System.Text;
+using UnityEngine;
+using UnityEngine.UI;
+using BlackRoad.Worldbuilder.Identity;
+
+namespace BlackRoad.Worldbuilder.Archive
+{
+    /// <summary>
+    /// Displays a simple list of all registered identities in the world.
+    /// Intended to sit under the Archive panel.
+    /// </summary>
+    public class IdentityListUI : MonoBehaviour
+    {
+        [SerializeField] private Text listText;
+        [SerializeField] private bool groupByType = true;
+
+        [Header("Refresh")]
+        [SerializeField] private float refreshInterval = 2f;
+
+        private float _timer;
+
+        private void Update()
+        {
+            _timer += Time.deltaTime;
+            if (_timer >= refreshInterval)
+            {
+                _timer = 0f;
+                Refresh();
+            }
+        }
+
+        public void Refresh()
+        {
+            if (listText == null) return;
+            var registry = WorldIdentityRegistry.Instance;
+            if (registry == null)
+            {
+                listText.text = "No registry found.";
+                return;
+            }
+
+            var ids = registry.Identities;
+            if (ids == null || ids.Count == 0)
+            {
+                listText.text = "No entities registered.";
+                return;
+            }
+
+            var sb = new StringBuilder();
+
+            if (groupByType)
+            {
+                foreach (WorldIdentity.EntityType type in System.Enum.GetValues(typeof(WorldIdentity.EntityType)))
+                {
+                    bool any = false;
+                    foreach (var id in ids)
+                    {
+                        if (id == null || id.Type != type) continue;
+                        if (!any)
+                        {
+                            any = true;
+                            sb.AppendLine($"== {type} ==");
+                        }
+
+                        sb.AppendLine($"- {id.DisplayName}  ({id.UniqueId.Substring(0, 6)}...)");
+                    }
+
+                    if (any) sb.AppendLine();
+                }
+            }
+            else
+            {
+                foreach (var id in ids)
+                {
+                    if (id == null) continue;
+                    sb.AppendLine($"{id.Type}: {id.DisplayName} ({id.UniqueId.Substring(0, 6)}...)");
+                }
+            }
+
+            listText.text = sb.ToString();
+        }
+    }
+}

Assets/Scripts/Identity/WorldIdentity.cs

@@ -0,0 +1,46 @@
+using UnityEngine;
+
+namespace BlackRoad.Worldbuilder.Identity
+{
+    /// <summary>
+    /// Assigns a stable identity to an entity in the world.
+    /// Used by the registry and archive to track critters, villagers, etc.
+    /// </summary>
+    public class WorldIdentity : MonoBehaviour
+    {
+        public enum EntityType
+        {
+            Unknown,
+            Critter,
+            Villager,
+            Structure,
+            Landmark,
+            Player
+        }
+
+        [Header("Identity")]
+        [SerializeField] private string uniqueId;
+        [SerializeField] private string displayName = "Entity";
+        [SerializeField] private EntityType type = EntityType.Unknown;
+
+        public string UniqueId => uniqueId;
+        public string DisplayName => displayName;
+        public EntityType Type => type;
+
+#if UNITY_EDITOR
+        private void OnValidate()
+        {
+            // If no ID assigned, generate a pseudo GUID once in editor
+            if (string.IsNullOrEmpty(uniqueId))
+            {
+                uniqueId = System.Guid.NewGuid().ToString("N");
+            }
+
+            if (string.IsNullOrEmpty(displayName))
+            {
+                displayName = gameObject.name;
+            }
+        }
+#endif
+    }
+}

Assets/Scripts/Identity/WorldIdentityAutoRegister.cs

@@ -0,0 +1,28 @@
+using UnityEngine;
+
+namespace BlackRoad.Worldbuilder.Identity
+{
+    /// <summary>
+    /// Helper that automatically registers a WorldIdentity with the registry.
+    /// </summary>
+    [RequireComponent(typeof(WorldIdentity))]
+    public class WorldIdentityAutoRegister : MonoBehaviour
+    {
+        private WorldIdentity _identity;
+
+        private void Awake()
+        {
+            _identity = GetComponent<WorldIdentity>();
+        }
+
+        private void OnEnable()
+        {
+            WorldIdentityRegistry.Instance?.Register(_identity);
+        }
+
+        private void OnDisable()
+        {
+            WorldIdentityRegistry.Instance?.Unregister(_identity);
+        }
+    }
+}

Assets/Scripts/Identity/WorldIdentityRegistry.cs

@@ -0,0 +1,55 @@
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace BlackRoad.Worldbuilder.Identity
+{
+    /// <summary>
+    /// Keeps track of all WorldIdentity components currently active in the scene.
+    /// Provides lookup and lists for Archive/UI.
+    /// </summary>
+    public class WorldIdentityRegistry : MonoBehaviour
+    {
+        public static WorldIdentityRegistry Instance { get; private set; }
+
+        private readonly List<WorldIdentity> _identities = new List<WorldIdentity>();
+
+        public IReadOnlyList<WorldIdentity> Identities => _identities;
+
+        private void Awake()
+        {
+            if (Instance != null && Instance != this)
+            {
+                Destroy(gameObject);
+                return;
+            }
+
+            Instance = this;
+            DontDestroyOnLoad(gameObject);
+        }
+
+        public void Register(WorldIdentity identity)
+        {
+            if (identity != null && !_identities.Contains(identity))
+            {
+                _identities.Add(identity);
+            }
+        }
+
+        public void Unregister(WorldIdentity identity)
+        {
+            if (identity != null)
+            {
+                _identities.Remove(identity);
+            }
+        }
+
+        public IEnumerable<WorldIdentity> GetByType(WorldIdentity.EntityType type)
+        {
+            foreach (var id in _identities)
+            {
+                if (id != null && id.Type == type)
+                    yield return id;
+            }
+        }
+    }
+}