Implements experience gain

PkmnLib.Dynamic/ScriptHandling/Registry/ScriptRegistry.cs

@@ -19,6 +19,7 @@ public class ScriptRegistry
     private IDamageCalculator? _damageCalculator;
     private IMiscLibrary? _miscLibrary;
     private ICaptureLibrary? _captureLibrary;
+    private IExperienceGainCalculator? _experienceGainCalculator;
 
     /// <summary>
     /// Automatically register all scripts in the given assembly that have the <see cref="ScriptAttribute"/>, and
@@ -110,11 +111,18 @@ public class ScriptRegistry
     public void RegisterCaptureLibrary<T>(T captureLibrary) where T : ICaptureLibrary =>
         _captureLibrary = captureLibrary;
 
+    /// <summary>
+    /// Register an experience gain calculator.
+    /// </summary>
+    public void RegisterExperienceGainCalculator<T>(T experienceGainCalculator) where T : IExperienceGainCalculator =>
+        _experienceGainCalculator = experienceGainCalculator;
+
     internal IReadOnlyDictionary<(ScriptCategory category, StringKey name), Func<Script>> ScriptTypes => _scriptTypes;
     internal IReadOnlyDictionary<StringKey, Func<IItem, ItemScript>> ItemScriptTypes => _itemScriptTypes;
     internal IBattleStatCalculator? BattleStatCalculator => _battleStatCalculator;
     internal IDamageCalculator? DamageCalculator => _damageCalculator;
     internal IMiscLibrary? MiscLibrary => _miscLibrary;
     internal ICaptureLibrary? CaptureLibrary => _captureLibrary;
+    internal IExperienceGainCalculator? ExperienceGainCalculator => _experienceGainCalculator;
     public ExplicitAIHandlers ExplicitAIHandlers { get; } = new();
 }