evict savestates on branch update

src/BizHawk.Client.Common/movie/interfaces/ITasMovie.cs

@@ -53,5 +53,7 @@ namespace BizHawk.Client.Common
 		void LoadBranch(TasBranch branch);
 
 		void CopyVerificationLog(IEnumerable<string> log);
+
+		bool IsReserved(int frame);
 	}
 }

src/BizHawk.Client.Common/movie/tasproj/TasBranch.cs

@@ -87,6 +87,9 @@ namespace BizHawk.Client.Common
 			newBranch.Uuid = old.Uuid;
 			if (newBranch.UserText.Length is 0) newBranch.UserText = old.UserText;
 			this[index] = newBranch;
+			if (!_movie.IsReserved(old.Frame))
+				_movie.TasStateManager.EvictReserved(old.Frame);
+
 			_movie.FlagChanges();
 		}
 
@@ -116,6 +119,9 @@ namespace BizHawk.Client.Common
 			var result = base.Remove(item);
 			if (result)
 			{
+				if (!_movie.IsReserved(item!.Frame))
+					_movie.TasStateManager.EvictReserved(item.Frame);
+
 				_movie.FlagChanges();
 			}
 

src/BizHawk.Client.Common/movie/tasproj/TasMovie.cs

@@ -340,7 +340,7 @@ namespace BizHawk.Client.Common
 		public void ClearChanges() => Changes = false;
 		public void FlagChanges() => Changes = true;
 
-		private bool IsReserved(int frame)
+		public bool IsReserved(int frame)
 		{
 			// Why the frame before?
 			// because we always navigate to the frame before and emulate 1 frame so that we ensure a proper frame buffer on the screen