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/t3-single-huge-quote.md

@@ -0,0 +1,11 @@
+### T3 · Single huge quote
+One quote, set big, centered, taking a whole section. No supporting text, no attribution boxes — attribution is a small caps line beneath.
+*Use when:* one quote is so good it earns the room.
+*Don't confuse with:* T1 Margin pull-quote (which is the *side* mate, not the *room*).
+
+```html
+<section class="proof-room">
+  <blockquote class="display-italic">"…"</blockquote>
+  <p class="attribution"><span class="caps">— Name, Company</span></p>
+</section>
+```