优化

common-event-contract/src/main/java/com/baiyue/common/event/EventDependencyNotReadyException.java

@@ -0,0 +1,7 @@
+package com.baiyue.common.event;
+
+/** Required business state has not arrived yet; retry the same event with backoff. */
+public class EventDependencyNotReadyException extends IllegalArgumentException {
+    public EventDependencyNotReadyException(String message) { super(message); }
+    public EventDependencyNotReadyException(String message, Throwable cause) { super(message, cause); }
+}

common-event-contract/src/main/java/com/baiyue/common/event/EventEnvelopeValidator.java

@@ -75,7 +75,7 @@ public final class EventEnvelopeValidator {
     public static void requireValid(EventEnvelope envelope) {
         List<String> errors = validate(envelope);
         if (!errors.isEmpty()) {
-            throw new IllegalArgumentException(String.join("；", errors));
+            throw new EventProtocolException(String.join("；", errors));
         }
     }
 

common-event-contract/src/main/java/com/baiyue/common/event/EventProtocolException.java

@@ -0,0 +1,7 @@
+package com.baiyue.common.event;
+
+/** An immutable event violates the consumption protocol; retrying unchanged data cannot fix it. */
+public class EventProtocolException extends IllegalArgumentException {
+    public EventProtocolException(String message) { super(message); }
+    public EventProtocolException(String message, Throwable cause) { super(message, cause); }
+}