feat(mq-starter): redis-stream 重试可放量（PEL reclaim + 超限落库）

- MqSubscription 增加 retryExhaustedHandler；registry 从 errorHandler 接线 RETRY_EXHAUSTED 回调
- redis driver 每轮 reclaim PEL：connection 层 xClaim 认领超 idle 消息并使 delivery+1
  - delivery <= maxRetry：重投消费，成功 ACK / 失败留 PEL
  - delivery > maxRetry：回调 retryExhaustedHandler 落库 + ACK 终止，不再卡队列
- 可配 reclaimMinIdleMs（默认 5000ms，对齐 legacy 5s 延迟）；4 参构造 + 3 参重载
- 集成测试连真实 redis 验证 重试耗尽→落库→ACK；全仓 28 测试绿

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mq-starter-core/src/main/java/com/njcn/mq/container/MqListenerRegistry.java

@@ -3,6 +3,7 @@ import com.njcn.mq.annotation.MqListener;
 import com.njcn.mq.core.MqContext;
 import com.njcn.mq.core.MqMessage;
 import com.njcn.mq.spi.MqConsumeErrorHandler;
+import com.njcn.mq.spi.MqErrorIdentity;
 import com.njcn.mq.spi.MqDriver;
 import com.njcn.mq.spi.MqIdempotentStore;
 import com.njcn.mq.spi.MqMessageListener;
@@ -33,29 +34,39 @@ public class MqListenerRegistry implements SmartLifecycle {
         if (running) return;
         for (MqListenerEndpoint ep : endpoints) {
             MqListener meta = ep.getMeta();
+            MqConsumeErrorHandler eh = resolveErrorHandler(meta);
+
             MqConsumeDispatcher.Builder db = MqConsumeDispatcher.builder()
                     .batchSize(meta.batchSize())
                     .consumer(batch -> consume(ep, batch));
             if (meta.idempotent()) {
                 db.idempotent(true).store(store);
             }
-            if (errorHandlerResolver != null && !meta.errorHandler().isEmpty()) {
-                MqConsumeErrorHandler eh = errorHandlerResolver.apply(meta.errorHandler());
-                if (eh != null) {
-                    db.errorHandler(eh);
-                }
+            if (eh != null) {
+                db.errorHandler(eh);
             }
             MqConsumeDispatcher dispatcher = db.build();
+
+            java.util.function.Consumer<MqMessage> retryExhausted = eh == null ? null
+                    : msg -> eh.onError(msg, MqErrorIdentity.RETRY_EXHAUSTED, null);
+
             MqSubscription sub = MqSubscription.builder()
                     .topic(meta.topic()).group(meta.group()).tag(meta.tag())
                     .payloadType(ep.getPayloadType())
                     .concurrency(meta.concurrency()).batchSize(meta.batchSize()).maxRetry(meta.maxRetry())
-                    .listener(dispatcher::dispatch).build();
+                    .listener(dispatcher::dispatch)
+                    .retryExhaustedHandler(retryExhausted)
+                    .build();
             driver.subscribe(sub);
         }
         running = true;
     }
 
+    private MqConsumeErrorHandler resolveErrorHandler(MqListener meta) {
+        if (errorHandlerResolver == null || meta.errorHandler().isEmpty()) return null;
+        return errorHandlerResolver.apply(meta.errorHandler());
+    }
+
     /** 业务调用适配：批量 endpoint 调 (List&lt;payload&gt;[,ctx])；单条 endpoint 逐条调 (payload[,ctx])。 */
     private void consume(MqListenerEndpoint ep, List<MqMessage> batch) throws Exception {
         if (ep.isBatch()) {

mq-starter-core/src/main/java/com/njcn/mq/spi/MqSubscription.java

@@ -1,6 +1,8 @@
 package com.njcn.mq.spi;
+import com.njcn.mq.core.MqMessage;
 import lombok.Builder;
 import lombok.Data;
+import java.util.function.Consumer;
 
 @Data
 @Builder
@@ -13,4 +15,6 @@ public class MqSubscription {
     private int batchSize;
     private int maxRetry;
     private MqMessageListener listener;
+    /** 重试耗尽（超过 maxRetry）时由 driver 回调，用于落库 RETRY_EXHAUSTED；可空。 */
+    private Consumer<MqMessage> retryExhaustedHandler;
 }

mq-starter-core/src/test/java/com/njcn/mq/container/MqListenerRegistryTest.java

@@ -61,6 +61,13 @@ class MqListenerRegistryTest {
             catch (Exception e) { throw new RuntimeException(e); }
         }
     }
+    /** fake driver：捕获 subscription，不喂消息。 */
+    static class CaptureDriver implements MqDriver {
+        MqSubscription captured;
+        @Override public void send(String topic, MqMessage m) {}
+        @Override public void stop() {}
+        @Override public void subscribe(MqSubscription s) { this.captured = s; }
+    }
     /** fake driver：subscribe 时按序喂多条消息。 */
     static class FeedDriver implements MqDriver {
         private final MqMessage[] msgs;
@@ -123,4 +130,23 @@ class MqListenerRegistryTest {
         assertEquals(1, errors.size(), "按名解析的 errorHandler 应被调用");
         assertEquals(MqErrorIdentity.SINGLE, errors.get(0));
     }
+
+    @Test
+    void retryExhaustedHandler_wiredFromErrorHandler() {
+        ErrBiz biz = new ErrBiz();
+        MqListenerAnnotationBeanPostProcessor bpp = new MqListenerAnnotationBeanPostProcessor();
+        bpp.postProcessAfterInitialization(biz, "biz");
+        List<MqErrorIdentity> errors = new ArrayList<>();
+        MqConsumeErrorHandler eh = (m, id, ex) -> errors.add(id);
+        Function<String, MqConsumeErrorHandler> resolver = name -> "myEH".equals(name) ? eh : null;
+        CaptureDriver driver = new CaptureDriver();
+        MqListenerRegistry reg = new MqListenerRegistry(driver, bpp.getEndpoints(), null, resolver);
+
+        reg.start();
+
+        assertNotNull(driver.captured.getRetryExhaustedHandler(), "应从 errorHandler 接线重试耗尽回调");
+        driver.captured.getRetryExhaustedHandler().accept(MqMessage.of("k", "", "p"));
+        assertEquals(1, errors.size());
+        assertEquals(MqErrorIdentity.RETRY_EXHAUSTED, errors.get(0), "重试耗尽应落库 RETRY_EXHAUSTED");
+    }
 }