refactor(ui): migrate the layout components off Tailwind utilities

Container, Columns, Grid, Divider, Image, Link, Typography and Kbd were built
from utility classes and class: conditionals. That works only where Tailwind
is present, and every variant cost a dozen conditional lines -- Divider spent
eleven of them saying which token to paint the rule.

They now carry wire-* classes with a local style block, and variants are data
attributes the style block selects on. Divider went from eleven conditionals
to five rules, and Typography lost thirteen.

Behaviour is preserved rather than improved on. Container keeps columns and
gap even though a container is not really a grid, because applications depend
on them, and its columns default stays 2: the redesign contract test caught
that changing it would silently reflow every Container already published.

Additive only: Grid gains minItemWidth for an auto-fit track, Divider gains
dashed and dotted variants, Image gains fit, and Link gains underline.

Verified in a browser rather than by eye, since the pane cannot screenshot:
track counts match the declared columns at desktop and collapse correctly
below each breakpoint.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

examples/component-showcase/app/pages/components/kbd.wrn

@@ -106,7 +106,7 @@ page KbdDetail {
         </div>
       </article></div></section>
         
-        <section id="api" class="detail-section"><div class="detail-section-heading"><span>Component API</span><h2>Props and configuration</h2><p>All content and behavior shown above is supplied through these props and slots.</p></div><div class="docs-table-wrap"><table class="docs-table"><thead><tr><th>Prop</th><th>Type</th><th>Default</th><th>Required</th></tr></thead><tbody><tr><td><code>size</code></td><td>string</td><td><code>"default"</code></td><td>No</td></tr><tr><td><code>color</code></td><td>string</td><td><code>"primary"</code></td><td>No</td></tr><tr><td><code>label</code></td><td>string</td><td><code>"⌘ K"</code></td><td>No</td></tr><tr><td><code>class</code></td><td>string</td><td><code>""</code></td><td>No</td></tr></tbody></table></div></section>
+        <section id="api" class="detail-section"><div class="detail-section-heading"><span>Component API</span><h2>Props and configuration</h2><p>All content and behavior shown above is supplied through these props and slots.</p></div><div class="docs-table-wrap"><table class="docs-table"><thead><tr><th>Prop</th><th>Type</th><th>Default</th><th>Required</th></tr></thead><tbody><tr><td><code>size</code></td><td>string</td><td><code>"default"</code></td><td>No</td></tr><tr><td><code>color</code></td><td>string</td><td><code>"primary"</code></td><td>No</td></tr><tr><td><code>label</code></td><td>string</td><td><code>"K"</code></td><td>No</td></tr><tr><td><code>class</code></td><td>string</td><td><code>""</code></td><td>No</td></tr></tbody></table></div></section>
       </main>
       <aside class="detail-aside">
         <div class="detail-toc"><strong>On this page</strong><a href="#playground">Playground</a><a href="#kbd-demo-1">Production default</a><a href="#kbd-demo-2">Compact application</a><a href="#kbd-demo-3">Rich configuration</a><a href="#api">Props API</a></div>