feat(docs): redesign portal with shared UI system

app/pages/packages/test.wrn

@@ -6,7 +6,7 @@ page wrnexustest {
 
   view {
     <div class="docs-shell">
-      <a class="skip-link" href="#main">Skip to content</a>
+      <SkipLink label="Skip to content" href="#main" class="docs-skip-link" />
       <header class="topbar">
         <a class="brand" href="/"><span>W</span> WRNexusJS</a>
         <nav aria-label="Primary"><a href="/getting-started">Get started</a><a href="/packages">Packages</a><a href="/language">Language</a><a href="/architecture">Architecture</a></nav>
@@ -186,7 +186,8 @@ test(&quot;health endpoint&quot;, async () =&gt; &#123;
 &#125;);</code></pre></article></div></section></article>
       <aside class="on-this-page"><h2>On this page</h2><nav><a class="toc-level-2" href="#guide">Guide</a><a class="toc-level-3" href="#overview">Overview</a><a class="toc-level-3" href="#api">API</a><a class="toc-level-4" href="#re-exported-test-primitives">Re-exported test primitives</a><a class="toc-level-4" href="#rendercomponent-source-props">renderComponent(source, props?)</a><a class="toc-level-4" href="#mounthtml-html">mountHtml(html)</a><a class="toc-level-4" href="#callroute-handler-request">callRoute(handler, request)</a><a class="toc-level-4" href="#createharness-projectroot-options">createHarness(projectRoot, options?)</a><a class="toc-level-3" href="#usage">Usage</a><a class="toc-level-3" href="#requirements-notes">Requirements / Notes</a><a class="toc-level-2" href="#api">Complete API</a><a class="toc-level-2" href="#examples">Examples</a></nav></aside>
     </main>
-      <footer>WRNexusJS 0.2.64 · Private Developer Preview · Bun-native · Documentation generated from installed package APIs.</footer>
+      <footer><div class="footer-brand"><span class="footer-mark" aria-hidden="true">W</span><p><strong>WRNexusJS 0.2.64</strong><span>Complete API documentation generated from installed package declarations.</span></p></div><nav aria-label="Footer"><a href="/packages">All packages</a><a href="/getting-started">Get started</a><a href="/security">Security</a><a href="/support">Support</a><a href="/llms.txt">AI guide</a></nav><p class="footer-meta">Private Developer Preview · Bun-native</p></footer>
+      <BackToTop />
     </div>
   }
 }