feat(docs): redesign portal with shared UI system

app/pages/packages/styles.wrn

@@ -6,7 +6,7 @@ page wrnexusstyles {
 
   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>
@@ -616,7 +616,8 @@ const themeJs = renderThemeRuntime(theme); // served at THEME_JS_HREF</code></pr
 &lt;button data-wire-theme-set=&quot;brand&quot;&gt;Brand theme&lt;/button&gt;</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="#config-loading">Config loading</a><a class="toc-level-4" href="#appconfig">AppConfig</a><a class="toc-level-4" href="#styles-pipeline">Styles pipeline</a><a class="toc-level-4" href="#theme-system">Theme system</a><a class="toc-level-3" href="#usage">Usage</a><a class="toc-level-4" href="#wrnexus-config-ts">wrnexus.config.ts</a><a class="toc-level-4" href="#loading-config-producing-css">Loading config + producing CSS</a><a class="toc-level-4" href="#rendering-the-theme">Rendering the theme</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>
   }
 }