asw-v01: archive deferred content (packs, site, lab, legacy examples)

- 2.1: packs/ -> archive/packs/
- 2.2: site/ -> archive/site/
- 2.3: src/lab/ -> archive/lab/
- 2.4: examples/ -> archive/examples-legacy/ (SSI-based)

archive/site/layouts/docs/single.html

@@ -0,0 +1,84 @@
+{{ define "content" }}
+  <section data-layout="docs">
+
+    <nav aria-label="Documentation" data-nav="sidebar">
+      {{- $top := .FirstSection -}}
+      {{- range $top.Sections.ByWeight -}}
+      <h3>{{ .Title }}</h3>
+      <ul>
+        {{- range .RegularPages.ByWeight -}}
+        <li>
+          <a href="{{ .RelPermalink }}"
+            {{- if eq .RelPermalink $.RelPermalink }} aria-current="page"{{ end -}}>
+            {{- .LinkTitle -}}
+          </a>
+        </li>
+        {{- end -}}
+      </ul>
+      {{- end -}}
+    </nav>
+
+    <article>
+      <header>
+        <h1>{{ .Title }}</h1>
+        {{- with .Description }}
+        <p>{{ . }}</p>
+        {{- end }}
+      </header>
+
+      {{ .Content }}
+
+      {{- if or .PrevInSection .NextInSection -}}
+      <footer data-role="prev-next">
+        {{- with .NextInSection -}}
+        <a href="{{ .RelPermalink }}" rel="prev">
+          <span aria-hidden="true">←</span> {{ .LinkTitle }}
+        </a>
+        {{- end -}}
+        {{- with .PrevInSection -}}
+        <a href="{{ .RelPermalink }}" rel="next">
+          {{ .LinkTitle }} <span aria-hidden="true">→</span>
+        </a>
+        {{- end -}}
+      </footer>
+      {{- end -}}
+    </article>
+
+    {{- with .TableOfContents -}}
+    <aside data-toc>
+      <h3>{{ i18n "onThisPage" | default "On this page" }}</h3>
+      {{ . }}
+    </aside>
+    {{- end -}}
+
+  </section>
+  <script>
+  // TOC scroll spy — highlights current section in the aside
+  (function(){
+    var toc = document.querySelector('[data-toc]');
+    if (!toc) return;
+    var links = toc.querySelectorAll('a');
+    if (!links.length) return;
+    var headings = [];
+    links.forEach(function(a) {
+      var id = a.getAttribute('href');
+      if (id && id.startsWith('#')) {
+        var el = document.getElementById(id.slice(1));
+        if (el) headings.push({ el: el, link: a });
+      }
+    });
+    if (!headings.length) return;
+    var observer = new IntersectionObserver(function(entries) {
+      entries.forEach(function(entry) {
+        if (entry.isIntersecting) {
+          links.forEach(function(a) { a.removeAttribute('aria-current'); });
+          headings.forEach(function(h) {
+            if (h.el === entry.target) h.link.setAttribute('aria-current', 'true');
+          });
+        }
+      });
+    }, { rootMargin: '0px 0px -70% 0px' });
+    headings.forEach(function(h) { observer.observe(h.el); });
+  })();
+  </script>
+{{ end }}