feat: stabilize Pi Web plugin API

docs/index.html

@@ -36,6 +36,7 @@
         <div class="nav-links">
           <a href="remote-first.html">Remote-first</a>
           <a href="install.html">Install</a>
+          <a href="plugins.html">Plugins</a>
           <a href="faq.html">FAQ</a>
           <a class="github-link" href="https://github.com/jmfederico/pi-web" aria-label="Pi Web on GitHub">
             <svg class="github-icon" viewBox="0 0 16 16" aria-hidden="true">
@@ -236,6 +237,14 @@
             </p>
             <a href="faq.html#is-this-linux-only">Read compatibility notes →</a>
           </article>
+          <article class="doc-card">
+            <h3>Local UI plugins?</h3>
+            <p>
+              Ask AI agents to add trusted local UI plugins from <code>~/.pi-web/plugins</code> without rebuilding or
+              restarting the session daemon.
+            </p>
+            <a href="plugins.html">Build a plugin →</a>
+          </article>
           <article class="doc-card">
             <h3>Node or tools not found?</h3>
             <p>
@@ -254,6 +263,7 @@
         <div class="footer-links">
           <a href="remote-first.html">Remote-first</a>
           <a href="install.html">Install</a>
+          <a href="plugins.html">Plugins</a>
           <a href="faq.html">FAQ</a>
           <a href="https://www.npmjs.com/package/@jmfederico/pi-web">npm</a>
         </div>