feat: add hallmark design skill

Anti-AI-slop design skill (greenfield pages, audits, redesigns, design
extraction from URLs/screenshots) -- installed and validated in an
earlier session, was sitting untracked. Full reference library:
components, macrostructures, themes, genres, verbs (audit/redesign).

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

skills/hallmark/references/components/t1-pull-quote-with-marginalia.md

@@ -0,0 +1,12 @@
+
+### T1 · Pull-quote with marginalia
+A quote sits in the wide column; the attribution and source link float in the narrow margin column.
+*Use when:* the page already has a marginalia rhythm (Tufte-leaning, editorial).
+*Don't confuse with:* T3 Single huge quote (which is centered and dominates).
+
+```html
+<aside class="proof-margin">
+  <blockquote class="serif-italic">"…"</blockquote>
+  <p class="attribution muted">— Name<br />Role, Company</p>
+</aside>
+```