Interface size setting: auto, large, medium or small on the world's pixel grid

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lang/sr.lang

@@ -264,6 +264,8 @@ val.medium = Средње
 val.high = Високо
 val.normal = Нормално
 val.large = Велико
+val.small = Мало
+val.auto_plain = Аутоматски
 
 # ---- key binding names
 key.cam_forward = Камера напред