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/_default/_markup/render-footnotes.html

@@ -0,0 +1,13 @@
+{{- /* render-footnotes.html
+     Replace Hugo's default <div class="footnotes"> with ASW-semantic markup.
+     Hugo v0.123.0+ render hook for the footnote block.
+     Ref: https://gohugo.io/render-hooks/footnotes/
+*/ -}}
+<footer data-role="footnotes">
+  <hr>
+  <ol>
+    {{- range .Items }}
+    <li id="{{ .ID }}">{{ .Content }}{{ .Return }}</li>
+    {{- end }}
+  </ol>
+</footer>