feat: Add WorldStateFlagAttribute and custom property drawer for enhanced dialogue management

- Implemented WorldStateFlagAttribute to mark string fields as world state flags.
- Created NarrativeNPCEditor for custom inspector to visualize dialogue version activation states.
- Developed WorldStateFlagDrawer to provide dropdown menu for known flags in the inspector.
- Introduced ActorModule for managing DialogueActorSO assets, including viewing, creating, and deleting actors.
- Added DialogueModule for managing DialogueSequenceSO assets with detailed previews and action bars.
- Established QuestModule for managing QuestSO assets, including objectives and branches.
- Implemented QuestManagerPostprocessor to automatically refresh QuestManager's quest list on asset changes.

Assets/_Game/Scripts/Dialogue/WorldStateFlagAttribute.cs

@@ -0,0 +1,10 @@
+using UnityEngine;
+
+namespace BaseGames.Dialogue
+{
+    /// <summary>
+    /// 标记一个 string 或 string[] 字段为世界状态标志 Key。
+    /// 在 Inspector 中会显示已知标志下拉菜单，支持直接输入新标志。
+    /// </summary>
+    public sealed class WorldStateFlagAttribute : PropertyAttribute { }
+}