when crop committed, set rating to (at least) 1

Program.cs

@@ -185,6 +185,9 @@ public class CropTool : ITool {
 
     if (input.IsKeyPressed(Keys.Enter)) {
       game.Cursor = MouseCursor.Default;
+      if (photo.Rating < 1) {
+        photo.Rating = 1;
+      }
       photo.ViewOffset = new(photo.Size.X / 2 - Rectangle.Center(r).X,
                              photo.Size.Y / 2 - Rectangle.Center(r).Y);
       return ToolStatus.Done;