fix(event-bridge): retain downstream business errors

event-bridge-service/src/main/java/com/baiyue/eventbridge/service/HttpLastlegEventClient.java

@@ -45,11 +45,31 @@ public class HttpLastlegEventClient implements LastlegEventClient {
                 .POST(HttpRequest.BodyPublishers.ofString(body))
                 .build();
         HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
-        JsonNode responseBody = objectMapper.readTree(response.body());
+        JsonNode responseBody;
+        try {
+            responseBody = objectMapper.readTree(response.body());
+        } catch (Exception ignored) {
+            responseBody = null;
+        }
         if (response.statusCode() / 100 != 2 || responseBody == null
                 || !"200".equals(responseBody.path("code").asText())) {
-            throw new IllegalStateException("尾程消费失败: HTTP " + response.statusCode());
+            throw new IllegalStateException(failureMessage(response.statusCode(), responseBody));
         }
         return String.valueOf(response.statusCode());
     }
+
+    static String failureMessage(int statusCode, JsonNode body) {
+        String code = body == null ? "missing" : body.path("code").asText("missing");
+        String message = body == null ? "non-json response" : body.path("message").asText("missing");
+        String requestId = body == null ? "missing" : body.path("requestId").asText("missing");
+        String traceId = body == null ? "missing" : body.path("traceId").asText("missing");
+        return "尾程消费失败: HTTP " + statusCode + ", code=" + bounded(code)
+            + ", message=" + bounded(message) + ", requestId=" + bounded(requestId)
+            + ", traceId=" + bounded(traceId);
+    }
+
+    private static String bounded(String value) {
+        String safe = value == null || value.isBlank() ? "missing" : value.replaceAll("[\\r\\n]+", " ");
+        return safe.length() <= 240 ? safe : safe.substring(0, 240);
+    }
 }

event-bridge-service/src/test/java/com/baiyue/eventbridge/service/HttpLastlegEventClientTest.java

@@ -0,0 +1,26 @@
+package com.baiyue.eventbridge.service;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class HttpLastlegEventClientTest {
+    private final ObjectMapper objectMapper = new ObjectMapper();
+
+    @Test
+    void failureIncludesBusinessCodeMessageAndTraceEvidence() throws Exception {
+        var body = objectMapper.readTree("""
+            {"code":"A0400","message":"入仓计划数据无效","requestId":"request-1","traceId":"trace-1"}
+            """);
+
+        assertThat(HttpLastlegEventClient.failureMessage(200, body))
+            .isEqualTo("尾程消费失败: HTTP 200, code=A0400, message=入仓计划数据无效, requestId=request-1, traceId=trace-1");
+    }
+
+    @Test
+    void nonJsonFailureIsStillDiagnosableWithoutLeakingRawBody() {
+        assertThat(HttpLastlegEventClient.failureMessage(502, null))
+            .isEqualTo("尾程消费失败: HTTP 502, code=missing, message=non-json response, requestId=missing, traceId=missing");
+    }
+}