feat: site restructure — layouts gallery, docs sections with inline demos

Navigation: Docs, Layouts, Lab (simplified from 6 items)

Layouts gallery: card grid showing all available page layouts
with live links to demo pages.

Docs restructure: 8 auto-generated sidebar sections
(Getting Started, Typography, Core, Content, Components,
Reference, Vault, Packs) with 20 new stub pages.
Each stub has inline HTML demos that ASW styles directly.

New Hugo layout template for layouts/ section.
Decap CMS nav updated.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

site/content/docs/getting-started/getting-started.md

@@ -0,0 +1,29 @@
+---
+title: "Quick Start"
+description: "Get ASW running in five minutes: one CSS file, semantic HTML, no build step."
+type: docs
+weight: 12
+date: 2026-04-11
+tags: ["getting-started", "installation"]
+ai-disclosure: "generated"
+ai-model: "claude-sonnet-4-6"
+ai-provider: "Anthropic"
+---
+
+Drop `asw.css` into your project, add one `<link>` tag, and write semantic HTML. No npm, no build pipeline, no configuration files required.
+
+## Inline Demo
+
+<div style="border:1px solid var(--border,#ccc);padding:1.5rem;border-radius:4px">
+  <nav style="margin-bottom:1rem">
+    <a href="#">Home</a> ·
+    <a href="#">Docs</a> ·
+    <a href="#">About</a>
+  </nav>
+  <main>
+    <article>
+      <header><h2>Page title</h2></header>
+      <p>This is an <code>&lt;article&gt;</code> inside <code>&lt;main&gt;</code>, next to a <code>&lt;nav&gt;</code>. ASW styles all three with no classes.</p>
+    </article>
+  </main>
+</div>