feat(io): make print(StyledText) the GameIO primitive; keep suite green

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -36,7 +36,7 @@ public class TestIO implements GameIO {
     }
 
     @Override
-    public void write(String s) {
-        outputs.add(s);
+    public void print(thb.jeanluc.adventure.io.text.StyledText text) {
+        outputs.add(text.plainText());
     }
 }