test(cdc): preserve zero Kafka retry semantics

cdc-service/src/main/java/com/xtrmetl/cdc/config/KafkaConfig.java

@@ -62,6 +62,14 @@ public DefaultErrorHandler kafkaListenerErrorHandler(
         return errorHandler;
     }
 
+    /**
+     * Builds the replica Kafka listener factory with record-level acknowledgement semantics.
+     *
+     * @param consumerFactory Kafka consumer factory for replica records
+     * @param kafkaListenerErrorHandler bounded retry and dead-letter error handler
+     * @param concurrency requested listener concurrency
+     * @return configured listener container factory
+     */
     @Bean
     public ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory(
             @NonNull ConsumerFactory<String, String> consumerFactory,

cdc-service/src/test/java/com/xtrmetl/cdc/config/KafkaConfigTest.java

@@ -54,6 +54,21 @@ void configuresErrorHandlerWithDeadLetterRecovererAndBackOff() {
         assertFalse(classifier.classify(new IllegalStateException("test")));
     }
 
+    @Test
+    void preservesZeroRetrySettings() {
+        KafkaConfig config = new KafkaConfig();
+        KafkaTemplate<String, String> kafkaTemplate = mock(KafkaTemplate.class);
+
+        DefaultErrorHandler errorHandler = config.kafkaListenerErrorHandler(kafkaTemplate, 0L, 0L);
+
+        Object failureTracker = ReflectionTestUtils.getField(errorHandler, "failureTracker");
+        assertNotNull(failureTracker);
+        FixedBackOff fixedBackOff = (FixedBackOff) ReflectionTestUtils.getField(failureTracker, "backOff");
+        assertNotNull(fixedBackOff);
+        assertEquals(0L, fixedBackOff.getInterval());
+        assertEquals(0L, fixedBackOff.getMaxAttempts());
+    }
+
     @Test
     void rejectsNegativeRetryBackoffBeforeBuildingErrorHandler() {
         KafkaConfig config = new KafkaConfig();