Add SIN.04028 tutorial material, tutor prompt and conversation log

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

SIN.04028-From-Calling-to-Eventing/supplemental-java/01-procedural/ProceduralRot13.java

@@ -0,0 +1,25 @@
+String rot13(String text) {
+    var result = new StringBuilder();
+
+    for (var character : text.toCharArray()) {
+        if (character >= 'a' && character <= 'z')
+            character = (char) ('a' + (character - 'a' + 13) % 26);
+        else if (character >= 'A' && character <= 'Z')
+            character = (char) ('A' + (character - 'A' + 13) % 26);
+
+        result.append(character);
+    }
+
+    return result.toString();
+}
+
+void main() {
+    while (true) {
+        var text = IO.readln();
+
+        if (text == null)
+            return;
+
+        IO.println(rot13(text));
+    }
+}