Add new miracles: Divine Mandate and Prosperity Boom; update buff application logic and game state calculations

Scripts/Core/Effects/Buff.cs

@@ -4,9 +4,10 @@ namespace ParasiticGod.Scripts.Core.Effects;
 
 public class Buff
 {
-    public Guid InstanceId { get; } = Guid.NewGuid(); // Unique identifier
-    public string BuffId { get; set; } // Identifier for the type of buff
-    public string Name { get; set; } // For display purposes
+    public Guid InstanceId { get; } = Guid.NewGuid();
+    public string BuffId { get; set; }
+    public string Name { get; set; }
+    public Stat TargetStat { get; set; }
     public float Multiplier { get; set; } = 1.0f;
     public double Duration { get; set; }
 }