add(tutorial): Include a new tutorial for creating an Agentic AI Java application with Spring AI

Author: Igor Souza

index.html

@@ -407,6 +407,14 @@ <h3>Create your first Java application</h3>
           <h3>Getting Started with Java by Devoxx4Kids</h3>
           <p>Installing and Fundamentals.</p>
         </a>
+
+        <a class="card" href="https://github.com/aws-samples/sample-once-upon-spring-ai" target="_blank" rel="noopener noreferrer">
+          <div class="card-badges">
+            <span class="card-badge badge-framework">Tutorial</span>
+          </div>
+          <h3>Create your first Agentic AI Java application with Spring AI</h3>
+          <p>A step-by-step tutorial to go from a coding apprentice to a game master of AI agent orchestration.</p>
+        </a>
       </div>
     </div>
   </section>