Add initial implementation of game mechanics and resources management

Scripts/Core/Effects/AddResourceEffect.cs

@@ -0,0 +1,29 @@
+using System;
+using Godot;
+
+namespace ParasiticGod.Scripts.Core.Effects;
+
+[GlobalClass]
+public partial class AddResourceEffect : Effect
+{
+    [Export] public ResourceType TargetResource { get; set; }
+    [Export] public double Value { get; set; }
+
+    public override void Execute(GameState state)
+    {
+        switch (TargetResource)
+        {
+            case ResourceType.Faith:
+                state.Faith += Value;
+                break;
+            case ResourceType.Followers:
+                state.Followers += (long)Value;
+                break;
+            case ResourceType.Corruption:
+                state.Corruption += Value;
+                break;
+            default:
+                throw new ArgumentOutOfRangeException();
+        }
+    }
+}