docs(website): highlight the setup guide on the homepage (#1714)

Show the hero's Setup guide link as a secondary button and add a link
to the step-by-step setup guide under the Set up REA panel.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

website/public/index.html

@@ -174,7 +174,7 @@
             </p>
             <div class="actions">
               <a class="button" href="#what-is-re">See how REA works ↓</a>
-              <a class="text-link" href="get-started/">Setup guide</a>
+              <a class="button secondary" href="get-started/">Setup guide</a>
               <a class="text-link" href="showcase/">Showcases →</a>
             </div>
             <p class="home-expert-shortcut">
@@ -229,6 +229,10 @@
             <p class="caption">
               Approve the setup plan, then restart your agent.
             </p>
+            <p class="home-expert-shortcut">
+              First time, or missing Node.js or a coding agent?
+              <a href="get-started/">Follow the step-by-step setup guide →</a>
+            </p>
           </div>
         </div>
       </section>