feat(rabbitmq): 新增死信队列（DLQ）支持

当前 RabbitMQ 已实现 Confirm + Returns + Retry，但缺少 DLQ 导致重试耗尽后消息直接丢失，无法追溯和人工补偿。

新增：
- RabbitMqDeadLetterConfig：声明 DLX 交换机及 send/recall 死信队列
- RabbitMqDeadLetterReceiver：消费死信消息，记录 headers 与 body 日志
- 主队列绑定 x-dead-letter-exchange / x-dead-letter-routing-key
- 配置 default-requeue-rejected=false，确保重试耗尽后进入 DLQ 而非 requeue

消息流向：
austin.queues.send/recall → 消费失败 → 重试 3 次 → 耗尽 →
austin.dlx → austin.queues.send.dead/recall.dead → 日志告警

austin-handler/src/main/java/com/java3y/austin/handler/receiver/rabbit/RabbitMqDeadLetterReceiver.java

@@ -0,0 +1,38 @@
+package com.java3y.austin.handler.receiver.rabbit;
+
+import com.java3y.austin.support.constans.MessageQueuePipeline;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.amqp.core.Message;
+import org.springframework.amqp.rabbit.annotation.RabbitListener;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.stereotype.Component;
+
+import java.nio.charset.StandardCharsets;
+
+/**
+ * 死信队列消费者
+ * 消费重试耗尽后进入 DLQ 的消息，记录日志便于排查与人工补偿
+ *
+ * @author Rangsh
+ */
+@Slf4j
+@Component
+@ConditionalOnProperty(name = "austin.mq.pipeline", havingValue = MessageQueuePipeline.RABBIT_MQ)
+public class RabbitMqDeadLetterReceiver {
+
+    @RabbitListener(queues = "${austin.rabbitmq.queues.send.dead}")
+    public void onSendDeadLetter(Message message) {
+        log.error("[DLQ][send] headers={}, body={}",
+                message.getMessageProperties().getHeaders(),
+                new String(message.getBody(), StandardCharsets.UTF_8));
+        // TODO: 后续可扩展落库 / 告警 / 人工补偿入口
+    }
+
+    @RabbitListener(queues = "${austin.rabbitmq.queues.recall.dead}")
+    public void onRecallDeadLetter(Message message) {
+        log.error("[DLQ][recall] headers={}, body={}",
+                message.getMessageProperties().getHeaders(),
+                new String(message.getBody(), StandardCharsets.UTF_8));
+        // TODO: 后续可扩展落库 / 告警 / 人工补偿入口
+    }
+}

austin-handler/src/main/java/com/java3y/austin/handler/receiver/rabbit/RabbitMqReceiver.java

@@ -9,6 +9,7 @@ import com.java3y.austin.support.constans.MessageQueuePipeline;
 import org.apache.commons.lang3.StringUtils;
 import org.springframework.amqp.core.ExchangeTypes;
 import org.springframework.amqp.core.Message;
+import org.springframework.amqp.rabbit.annotation.Argument;
 import org.springframework.amqp.rabbit.annotation.Exchange;
 import org.springframework.amqp.rabbit.annotation.Queue;
 import org.springframework.amqp.rabbit.annotation.QueueBinding;
@@ -33,7 +34,14 @@ public class RabbitMqReceiver implements MessageReceiver {
     private ConsumeService consumeService;
 
     @RabbitListener(bindings = @QueueBinding(
-            value = @Queue(value = "${spring.rabbitmq.queues.send}", durable = "true"),
+            value = @Queue(
+                    value = "${spring.rabbitmq.queues.send}",
+                    durable = "true",
+                    arguments = {
+                            @Argument(name = "x-dead-letter-exchange", value = "${austin.rabbitmq.dlx.exchange}"),
+                            @Argument(name = "x-dead-letter-routing-key", value = "${austin.rabbitmq.routing.send.dead}")
+                    }
+            ),
             exchange = @Exchange(value = "${austin.rabbitmq.exchange.name}", type = ExchangeTypes.TOPIC),
             key = "${austin.rabbitmq.routing.send}"
     ))
@@ -49,7 +57,14 @@ public class RabbitMqReceiver implements MessageReceiver {
     }
 
     @RabbitListener(bindings = @QueueBinding(
-            value = @Queue(value = "${spring.rabbitmq.queues.recall}", durable = "true"),
+            value = @Queue(
+                    value = "${spring.rabbitmq.queues.recall}",
+                    durable = "true",
+                    arguments = {
+                            @Argument(name = "x-dead-letter-exchange", value = "${austin.rabbitmq.dlx.exchange}"),
+                            @Argument(name = "x-dead-letter-routing-key", value = "${austin.rabbitmq.routing.recall.dead}")
+                    }
+            ),
             exchange = @Exchange(value = "${austin.rabbitmq.exchange.name}", type = ExchangeTypes.TOPIC),
             key = "${austin.rabbitmq.routing.recall}"
     ))

austin-support/src/main/java/com/java3y/austin/support/config/RabbitMqDeadLetterConfig.java

@@ -0,0 +1,66 @@
+package com.java3y.austin.support.config;
+
+import com.java3y.austin.support.constans.MessageQueuePipeline;
+import org.springframework.amqp.core.Binding;
+import org.springframework.amqp.core.BindingBuilder;
+import org.springframework.amqp.core.DirectExchange;
+import org.springframework.amqp.core.Queue;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * RabbitMQ 死信队列配置
+ * 重试耗尽后消息进入 DLQ，避免消息丢失，便于人工排查与补偿
+ *
+ * @author Rangsh
+ */
+@Configuration
+@ConditionalOnProperty(name = "austin.mq.pipeline", havingValue = MessageQueuePipeline.RABBIT_MQ)
+public class RabbitMqDeadLetterConfig {
+
+    @Value("${austin.rabbitmq.dlx.exchange}")
+    private String dlxExchangeName;
+
+    @Value("${austin.rabbitmq.queues.send.dead}")
+    private String sendDeadQueueName;
+
+    @Value("${austin.rabbitmq.queues.recall.dead}")
+    private String recallDeadQueueName;
+
+    @Value("${austin.rabbitmq.routing.send.dead}")
+    private String sendDeadRoutingKey;
+
+    @Value("${austin.rabbitmq.routing.recall.dead}")
+    private String recallDeadRoutingKey;
+
+    @Bean
+    public DirectExchange deadLetterExchange() {
+        return new DirectExchange(dlxExchangeName, true, false);
+    }
+
+    @Bean
+    public Queue sendDeadLetterQueue() {
+        return new Queue(sendDeadQueueName, true);
+    }
+
+    @Bean
+    public Queue recallDeadLetterQueue() {
+        return new Queue(recallDeadQueueName, true);
+    }
+
+    @Bean
+    public Binding sendDeadLetterBinding() {
+        return BindingBuilder.bind(sendDeadLetterQueue())
+                .to(deadLetterExchange())
+                .with(sendDeadRoutingKey);
+    }
+
+    @Bean
+    public Binding recallDeadLetterBinding() {
+        return BindingBuilder.bind(recallDeadLetterQueue())
+                .to(deadLetterExchange())
+                .with(recallDeadRoutingKey);
+    }
+}

austin-web/src/main/resources/application.properties

@@ -71,11 +71,19 @@ spring.rabbitmq.listener.simple.retry.enabled=true
 spring.rabbitmq.listener.simple.retry.initial-interval=1000
 spring.rabbitmq.listener.simple.retry.multiplier=2
 spring.rabbitmq.listener.simple.retry.max-attempts=3
+# retry exhausted → reject (no requeue) → DLQ
+spring.rabbitmq.listener.simple.default-requeue-rejected=false
 austin.rabbitmq.exchange.name=austin.point
 spring.rabbitmq.queues.send=austin.queues.send
 spring.rabbitmq.queues.recall=austin.queues.recall
 austin.rabbitmq.routing.send=austin.send
 austin.rabbitmq.routing.recall=austin.recall
+# dead letter
+austin.rabbitmq.dlx.exchange=austin.dlx
+austin.rabbitmq.queues.send.dead=austin.queues.send.dead
+austin.rabbitmq.queues.recall.dead=austin.queues.recall.dead
+austin.rabbitmq.routing.send.dead=austin.send.dead
+austin.rabbitmq.routing.recall.dead=austin.recall.dead
 ########################################## RabbitMq end ##########################################