Added the system from trail

Runtime/EncounterTable.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace Jovian.EncounterSystem {
+    /// <summary>
+    /// A ScriptableObject asset holding a named list of encounters. Encounters inside the list are
+    /// authored via <c>[SerializeReference]</c> so different <see cref="IEncounter"/> implementations
+    /// and <see cref="IEncounterKind"/> payloads can coexist.
+    /// </summary>
+    [CreateAssetMenu(fileName = "EncounterTable", menuName = "Jovian/Encounter System/Encounter Table", order = 1)]
+    public class EncounterTable : ScriptableObject {
+        /// <summary>Designer-facing table identifier (free-form).</summary>
+        public string id;
+
+        /// <summary>Ordered encounter list. Each element is a concrete <see cref="Encounter"/> whose
+        /// type-specific payload is carried by its <see cref="IEncounterKind"/> (set in the inspector
+        /// via the SubclassSelector dropdown on <see cref="Encounter.Kind"/>).</summary>
+        public List<Encounter> encounters;
+
+        /// <summary>Pick a uniformly random encounter, or <c>null</c> if the table is empty.</summary>
+        public IEncounter GetRandomEncounter() {
+            if(encounters == null || encounters.Count == 0) {
+                return null;
+            }
+
+            return encounters[UnityEngine.Random.Range(0, encounters.Count)];
+        }
+
+        /// <summary>Pick a uniformly random encounter whose runtime type matches <paramref name="type"/>,
+        /// or <c>null</c> if none match.</summary>
+        /// <param name="type">The concrete <see cref="IEncounter"/> runtime type to filter on.</param>
+        public IEncounter GetRandomEncounter(Type type) {
+            if(encounters == null || encounters.Count == 0) {
+                return null;
+            }
+
+            var encountersOfType = encounters.FindAll(encounter => encounter.GetType() == type);
+            if(encountersOfType.Count > 0) {
+                return encountersOfType[UnityEngine.Random.Range(0, encountersOfType.Count)];
+            }
+
+            return null;
+        }
+
+        /// <summary>Pick a uniformly random encounter matching <paramref name="filter"/>, or <c>null</c>
+        /// if no element passes. Used by <see cref="QuestProgress.IsGated"/> integration to exclude
+        /// gated quest encounters from rolls.</summary>
+        /// <param name="filter">Predicate applied to each encounter before rolling.</param>
+        public IEncounter GetRandomEncounter(Predicate<IEncounter> filter) {
+            if(encounters == null || encounters.Count == 0 || filter == null) {
+                return GetRandomEncounter();
+            }
+
+            var pool = encounters.FindAll(filter);
+            if(pool.Count == 0) {
+                return null;
+            }
+
+            return pool[UnityEngine.Random.Range(0, pool.Count)];
+        }
+    }
+}