Add initial implementation of game mechanics and resources management

Scripts/Core/GameLogic.cs

@@ -0,0 +1,43 @@
+using System;
+
+namespace ParasiticGod.Scripts.Core;
+
+public class GameLogic
+{
+    public void UpdateGameState(GameState state, double delta)
+    {
+        state.Faith += state.FaithPerSecond * delta;
+
+        for (var i = state.ActiveBuffs.Count - 1; i >= 0; i--)
+        {
+            var buff = state.ActiveBuffs[i];
+            buff.Duration -= delta;
+            if (buff.Duration <= 0)
+            {
+                state.ActiveBuffs.RemoveAt(i);
+            }
+        }
+    }
+
+    public bool TryToPerformMiracle(GameState state, MiracleDefinition miracle)
+    {
+        if (state.Faith < miracle.FaithCost || state.Followers < miracle.FollowersRequired)
+        {
+            return false;
+        }
+
+        state.Faith -= miracle.FaithCost;
+        
+        if (miracle.Effects != null)
+        {
+            foreach (var effect in miracle.Effects)
+            {
+                effect.Execute(state);
+            }
+        }
+        
+        state.Corruption = Math.Clamp(state.Corruption, 0, 100);
+
+        return true;
+    }
+}