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/03-static-filesystem/ProcessorService.java

@@ -0,0 +1,30 @@
+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() throws Exception {
+    FileMessageBoard.watch("rot13/inbox", message -> {
+        if (!message.type().equals("TEXT"))
+            return;
+
+        try {
+            FileMessageBoard.publish(
+                "rot13/outbox",
+                new Message("TEXT", rot13(message.value()))
+            );
+        } catch (IOException exception) {
+            throw new UncheckedIOException(exception);
+        }
+    });
+}