feat(docs): redesign portal with shared UI system

scripts/generate-docs.ts

@@ -256,7 +256,7 @@ function shell(title: string, description: string, content: string, state = ""):
 ${state}
   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>
@@ -264,7 +264,8 @@ ${state}
       </header>
       <div class="mobile-doc-nav"><details><summary>Browse documentation</summary><nav><a href="/getting-started">Get started</a><a href="/packages">Packages</a><a href="/language">Language</a><a href="/architecture">Architecture</a><a href="/tutorial">Tutorial</a><a href="/guides/project-structure">Guides</a><a href="/examples">Examples</a><a href="/search">Search</a></nav></details></div>
       ${content}
-      <footer>WRNexusJS ${frameworkVersion} · 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 ${frameworkVersion}</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>
   }
 }