fix: add mutex to prevent multiple scenarios from running at once

src/PepperDash.Essentials.Core/Room/Combining/EssentialsRoomCombiner.cs

@@ -5,6 +5,7 @@ using Serilog.Events;
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 
 namespace PepperDash.Essentials.Core
 {
@@ -48,6 +49,8 @@ namespace PepperDash.Essentials.Core
 
         private int _scenarioChangeDebounceTimeSeconds = 10; // default to 10s
 
+        private Mutex _scenarioChange = new Mutex();
+
         public EssentialsRoomCombiner(string key, EssentialsRoomCombinerPropertiesConfig props)
             : base(key)
         {
@@ -205,6 +208,10 @@ namespace PepperDash.Essentials.Core
             }
             private set
             {
+                try
+                {
+                    _scenarioChange.WaitOne();
+
                     if (value != _currentScenario)
                     {
                         // Deactivate the old scenario first
@@ -230,6 +237,11 @@ namespace PepperDash.Essentials.Core
                         }
                     }
                 }
+                finally
+                {
+                    _scenarioChange.ReleaseMutex();
+                }
+            }
         }
 
         public BoolFeedback IsInAutoModeFeedback { get; private set; }