added encounter system

Packages/com.jovian.encounter-system/Runtime/Reward.cs

@@ -0,0 +1,13 @@
+using UnityEngine;
+
+namespace Jovian.EncounterSystem {
+    /// <summary>Reusable reward asset referenced by <see cref="GiveRewardEvent"/>.</summary>
+    [CreateAssetMenu(fileName = "Reward", menuName = "Jovian/Encounter System/Reward", order = 3)]
+    public class Reward : ScriptableObject {
+        public string id;
+        public string displayName;
+
+        [SerializeReference, SubclassSelector]
+        public IRewardKind kind;
+    }
+}