fixed minor access bug

Core/src/main/java/me/neurodock/backend/open/ai/OpenAIAssistentMessage.java

@@ -25,7 +25,7 @@ public class OpenAIAssistentMessage extends Message {
         return endReason;
     }
 
-    enum Reason {
+    public static enum Reason {
         STOP,
         LENGTH,
         TOOL_CALLS,

gradle.properties

@@ -2,6 +2,6 @@
 useAPI = true
 javaVersion = 25
 
-coreVersion = 2.1.5
+coreVersion = 2.1.5.1
 pluginAPIVersion = 1.1.4.1
 APIVersion = 1.0-SNAPSHOT