feat: add [data-demo] attribute, purge all inline CSS from docs

New data-demo attribute for demo blocks in documentation.
Replaced 16 files worth of inline style="" wrappers with <div data-demo>.
Only remaining style= is charts --size data injection (legitimate).

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

site/content/docs/components/buttons.md

@@ -14,7 +14,7 @@ ai-provider: "Anthropic"
 
 ## Inline Demo
 
-<div style="border:1px solid var(--border,#ccc);padding:1.5rem;border-radius:4px;display:flex;gap:0.75rem;flex-wrap:wrap;align-items:center">
+<div data-demo>
   <button>Primary</button>
   <button data-variant="secondary">Secondary</button>
   <button data-variant="danger">Danger</button>

site/content/docs/components/callouts.md

@@ -14,7 +14,7 @@ Add `data-callout="<type>"` to any block element to style it as a callout. Four
 
 ## Inline Demo
 
-<div style="border:1px solid var(--border,#ccc);padding:1.5rem;border-radius:4px;display:flex;flex-direction:column;gap:1rem">
+<div data-demo>
   <div data-callout="note"><strong>Note</strong> — General information worth highlighting.</div>
   <div data-callout="tip"><strong>Tip</strong> — A helpful suggestion or best practice.</div>
   <div data-callout="warning"><strong>Warning</strong> — Something to watch out for.</div>

site/content/docs/components/dialog.md

@@ -14,7 +14,7 @@ ASW styles the native `<dialog>` element — no JavaScript modal libraries requi
 
 ## Inline Demo
 
-<div style="border:1px solid var(--border,#ccc);padding:1.5rem;border-radius:4px">
+<div data-demo>
   <button onclick="document.getElementById('demo-dialog').showModal()">Open dialog</button>
   <dialog id="demo-dialog">
     <article>

site/content/docs/components/forms.md

@@ -14,8 +14,8 @@ All standard form elements are styled out of the box. Labels, inputs, selects, a
 
 ## Inline Demo
 
-<div style="border:1px solid var(--border,#ccc);padding:1.5rem;border-radius:4px">
-  <form style="display:flex;flex-direction:column;gap:1rem;max-width:28rem" onsubmit="return false">
+<div data-demo>
+  <form onsubmit="return false">
     <label>
       Name
       <input type="text" placeholder="Jane Smith">