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/packs/hugo/layouts/shortcodes/callout.html

@@ -0,0 +1,16 @@
+{{- /*
+  callout shortcode — wraps content in an ASW callout block.
+  
+  Usage:
+    {{< callout note >}}
+    Content here. Markdown is rendered.
+    {{< /callout >}}
+  
+  First positional param: callout type.
+  Valid types: note, warning, tip, info (maps to ASW data-callout attribute).
+  Default: note
+*/ -}}
+{{- $type := .Get 0 | default "note" -}}
+<aside data-callout="{{ $type }}">
+  {{ .Inner | markdownify }}
+</aside>