Added the system from trail

Runtime/IEncounter.cs

@@ -0,0 +1,92 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace Jovian.EncounterSystem {
+    /// <summary>
+    /// Runtime contract for any encounter authored in the system.
+    /// An encounter aggregates designer-facing metadata, visuals, dialog, and a polymorphic
+    /// <see cref="IEncounterKind"/> payload that expresses its type-specific data.
+    /// </summary>
+    public interface IEncounter {
+        /// <summary>Stable identity, display name, and designer description.</summary>
+        EncounterDefinition EncounterDefinition { get; set; }
+
+        /// <summary>Numeric configuration shared by every encounter kind.</summary>
+        EncounterProperties EncounterProperties { get; set; }
+
+        /// <summary>Visual assets displayed when the encounter is presented.</summary>
+        EncounterVisuals EncounterVisuals { get; set; }
+
+        /// <summary>Dialog options shown to the player, or <c>null</c> if the encounter has no dialog.</summary>
+        EncounterDialogOptionSet EncounterDialogOptionSet { get; set; }
+
+        /// <summary>Type-specific payload (combat, quest, social, ...). Authored via the SubclassSelector drawer.</summary>
+        IEncounterKind Kind { get; set; }
+    }
+
+    /// <summary>
+    /// Default concrete encounter. Holds the shared fields and a polymorphic <see cref="IEncounterKind"/>.
+    /// Prefer adding new behaviour by introducing a new <see cref="IEncounterKind"/> rather than subclassing this type.
+    /// </summary>
+    [Serializable]
+    public class Encounter : IEncounter {
+        [field: SerializeField] public EncounterDefinition EncounterDefinition { get; set; }
+        [field: SerializeField] public EncounterProperties EncounterProperties { get; set; }
+        [field: SerializeField] public EncounterVisuals EncounterVisuals { get; set; }
+        [field: SerializeField] public EncounterDialogOptionSet EncounterDialogOptionSet { get; set; }
+
+        [field: SerializeReference, SubclassSelector]
+        public IEncounterKind Kind { get; set; }
+    }
+
+    /// <summary>
+    /// Designer-facing identity for an encounter. <see cref="internalId"/> is the stable GUID used for
+    /// cross-references (<see cref="EncounterLink"/>, quest progress, save data); <see cref="id"/> is a
+    /// human-readable slug; <see cref="name"/> and <see cref="description"/> are display strings.
+    /// </summary>
+    [Serializable]
+    public class EncounterDefinition {
+        /// <summary>Stable GUID, assigned once at creation. Never edit manually.</summary>
+        [HideInInspector]
+        public string internalId = Guid.NewGuid().ToString();
+
+        /// <summary>Designer-authored short slug (e.g. "goblin_ambush").</summary>
+        public string id;
+
+        /// <summary>Display name shown to the player.</summary>
+        public string name;
+
+        /// <summary>Flavour text shown when the encounter opens.</summary>
+        public string description;
+    }
+
+    /// <summary>
+    /// A single choice presented to the player inside an <see cref="EncounterDialogOptionSet"/>.
+    /// Events fire in order when the option is picked and are dispatched through <see cref="EncounterResolver"/>.
+    /// </summary>
+    [Serializable]
+    public class EncounterDialogOption {
+        /// <summary>Option text shown in the UI. Resolved through a shared
+        /// <see cref="DialogLineLibrary"/> or falls back to inline text.</summary>
+        public DialogLineRef text;
+
+        /// <summary>Ordered events executed by the resolver when this option is chosen.</summary>
+        [SerializeReference, SubclassSelector]
+        public List<IEncounterEvent> events;
+    }
+
+    /// <summary>Visual assets for an encounter.</summary>
+    [Serializable]
+    public class EncounterVisuals {
+        public Sprite icon;
+        public Color encounterColor;
+        public Sprite encounterArt;
+    }
+
+    /// <summary>Numeric/tuning configuration shared across every encounter kind.</summary>
+    [Serializable]
+    public class EncounterProperties {
+        public int difficulty;
+    }
+}