feat(io): travelStep hook for animated auto-walk (console no-op, Swing override)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Semesterprojekt/src/test/java/thb/jeanluc/adventure/io/TravelStepDefaultTest.java

@@ -0,0 +1,19 @@
+package thb.jeanluc.adventure.io;
+
+import org.junit.jupiter.api.Test;
+import thb.jeanluc.adventure.io.text.MapView;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class TravelStepDefaultTest {
+
+    @Test
+    void defaultTravelStepIsSilentNoOp() {
+        TestIO io = new TestIO();
+        // An empty map view is fine; the default must not print or throw.
+        io.travelStep(new MapView(List.of(), List.of()));
+        assertThat(io.outputs()).isEmpty();
+    }
+}