fold(hitl): R3 round 1 — dedupe setUp endpoint() + narrow exception class

R3 round 1 surfaced two folds against the Java HITL PR:

- MED-1: HITLTest.setUp called .endpoint(wmRuntimeInfo.getHttpBaseUrl())
  twice on the same builder (copy-paste bug, harmless at runtime but a
  real code-smell). Collapsed to a single chained call.
- MED-5: All three platform-error tests (400 bad-notify_url-scheme, 401
  auth, network failure via CONNECTION_RESET_BY_PEER) asserted
  .isInstanceOf(Exception.class) which would pass even on
  NullPointerException. Narrowed to AxonFlowException.class to match
  the @throws AxonFlowException javadoc at AxonFlow.java:6440 and the
  required-field guard tests at lines 387/397/407 which already narrow
  to IllegalArgumentException.

Tests still green: 25/25 in HITLTest (8 under CreateHITLRequest).

Refs getaxonflow/axonflow-enterprise#2421

Signed-off-by: Saurabh Jain <saurabh.jain@getaxonflow.com>

Author: saurabhjain1592

src/test/java/com/getaxonflow/sdk/HITLTest.java

@@ -18,6 +18,7 @@
 import static com.github.tomakehurst.wiremock.client.WireMock.*;
 import static org.assertj.core.api.Assertions.*;
 
+import com.getaxonflow.sdk.exceptions.AxonFlowException;
 import com.getaxonflow.sdk.types.hitl.HITLTypes.*;
 import com.github.tomakehurst.wiremock.junit5.WireMockRuntimeInfo;
 import com.github.tomakehurst.wiremock.junit5.WireMockTest;
@@ -77,11 +78,7 @@ class HITLTest {
   @BeforeEach
   void setUp(WireMockRuntimeInfo wmRuntimeInfo) {
     axonflow =
-        AxonFlow.create(
-            AxonFlowConfig.builder()
-                .endpoint(wmRuntimeInfo.getHttpBaseUrl())
-                .endpoint(wmRuntimeInfo.getHttpBaseUrl())
-                .build());
+        AxonFlow.create(AxonFlowConfig.builder().endpoint(wmRuntimeInfo.getHttpBaseUrl()).build());
   }
 
   // ========================================================================
@@ -334,7 +331,8 @@ void shouldSurfaceBadNotifyUrlSchemeAsException() {
               .notifyUrl("javascript:alert(1)")
               .build();
 
-      assertThatThrownBy(() -> axonflow.createHITLRequest(input)).isInstanceOf(Exception.class);
+      assertThatThrownBy(() -> axonflow.createHITLRequest(input))
+          .isInstanceOf(AxonFlowException.class);
     }
 
     @Test
@@ -355,7 +353,8 @@ void shouldPropagateAuthFailure() {
               .requestType("adk-tool")
               .build();
 
-      assertThatThrownBy(() -> axonflow.createHITLRequest(input)).isInstanceOf(Exception.class);
+      assertThatThrownBy(() -> axonflow.createHITLRequest(input))
+          .isInstanceOf(AxonFlowException.class);
     }
 
     @Test
@@ -376,7 +375,8 @@ void shouldPropagateNetworkFailure() {
               .requestType("adk-tool")
               .build();
 
-      assertThatThrownBy(() -> axonflow.createHITLRequest(input)).isInstanceOf(Exception.class);
+      assertThatThrownBy(() -> axonflow.createHITLRequest(input))
+          .isInstanceOf(AxonFlowException.class);
     }
 
     @Test