[+] Play "Master" difficulty on Demo screen

AquaMai/UX/DemoMaster.cs

@@ -0,0 +1,27 @@
+using DB;
+using HarmonyLib;
+using MAI2.Util;
+using Manager;
+using Process;
+
+namespace AquaMai.UX
+{
+    public class DemoMaster
+    {
+        [HarmonyPostfix]
+        [HarmonyPatch(typeof(AdvDemoProcess), "OnStart")]
+        public static void AdvDemoProcessPostStart()
+        {
+            var userOption = Singleton<GamePlayManager>.Instance.GetGameScore(0).UserOption;
+            userOption.NoteSpeed = OptionNotespeedID.Speed7_0;
+        }
+        
+        [HarmonyPrefix]
+        [HarmonyPatch(typeof(GamePlayManager), "InitializeAdvertise")]
+        public static void PreInitializeAdvertise()
+        {
+            GameManager.SelectDifficultyID[0] = 3;
+            GameManager.SelectDifficultyID[1] = 3;
+        }
+    }
+}