refactor(dynamic): add multi-method support to RouteShape, update framework bindings, and improve test coverage

tests/dynamic_fixtures/message_handler/kafka_java/Benign.java

@@ -1,8 +1,11 @@
 // Phase 20 (Track M.2) — Kafka Java benign control.
-// `org.springframework.kafka` adapter marker preserved.
+
+import org.springframework.kafka.annotation.KafkaListener;
+
 public class Benign {
     public Benign() {}
 
+    @KafkaListener(topics = "orders")
     public void onMessage(String body) throws Exception {
         new ProcessBuilder("echo", body).inheritIO().start().waitFor();
     }