fix deserialization error in native image

backend/src/main/java/com/aiteacher/config/NativeHintsConfig.java

@@ -5,6 +5,8 @@ import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.RuntimeHintsRegistrar;
 import org.springframework.aot.hint.TypeReference;
 
+import java.util.List;
+
 /**
  * GraalVM native-image runtime hints for third-party libraries that use reflection
  * or classpath resource scanning not covered by Spring Boot's AOT processor.
@@ -64,6 +66,20 @@ public class NativeHintsConfig implements RuntimeHintsRegistrar {
                 software.amazon.awssdk.services.s3.S3Client.class,
                 MemberCategory.INVOKE_PUBLIC_METHODS
         );
+
+        // Jackson deserialization of records persisted as JSON in DB columns.
+        // These are reached only via ObjectMapper.readValue in services, so Spring's
+        // BindingReflectionHintsRegistrar does not auto-discover all accessors.
+        for (Class<?> type : List.of(
+                com.aiteacher.topic.TopicSummaryResponse.class,
+                com.aiteacher.topic.TopicSummaryResponse.SourceReference.class,
+                com.aiteacher.concept.ConceptReportResponse.class,
+                com.aiteacher.concept.ConceptReportResponse.FacetSection.class
+        )) {
+            hints.reflection().registerType(type,
+                    MemberCategory.INVOKE_DECLARED_CONSTRUCTORS,
+                    MemberCategory.INVOKE_DECLARED_METHODS);
+        }
     }
 
     private void registerJBossLogger(RuntimeHints hints, String className) {