feat(site): rework 19 marketing showcases for composition diversity

Measured convergence before: split hero 13/19, top-bar nav 19/19,
one-line notice footer 14/19, body Pretendard 17/21, 10 similarity
pairs above 0.78. Each showcase got a pre-assigned hero family, nav
form, footer form, type pair, background, accent hue, radius, motion
grammar and material from outputs/rework-2026-10-06/plan.md; direction
cards and the chosen reason are recorded in every design.md.

After: 0 similarity warnings, 19 distinct display faces, 7 hero
families, 5 nav forms, 5 footer forms, no scroll reveals, 5 showcases
with SVG filter materials. Example contact values replace bracket
placeholders under the existing fictional-brand notices. Thumbnails,
OG images, card copy and three e2e assertions updated; dead CSS in
dure-enrollment and hannam-jari removed; similarity.mjs learns the new
font families.

apps/site/tools/integrity.mjs

@@ -163,7 +163,9 @@ for (const slug of showcases) {
   if (/word-break:\s*keep-all/.test(all)) ok(`${slug} keep-all`);
   else fail(`${slug} keep-all`, "한글 조판 필수 규칙 word-break: keep-all 이 없다");
 
-  if (/Pretendard|Noto Sans KR|본고딕|MaruBuri|마루부리/.test(all)) ok(`${slug} 한글 폰트 지정`);
+  // 특정 서체를 강제하지 않는다 — 한글 글리프가 있는 서체를 하나라도 명시하면 된다.
+  // 예전 목록(Pretendard·Noto Sans KR·마루부리)만 허용하던 것이 서체 수렴을 부추겼다.
+  if (/Pretendard|Noto Sans KR|Noto Serif KR|본고딕|MaruBuri|마루부리|SUIT|Wanted Sans|IBM Plex Sans KR|Gothic A1|Nanum|Gowun|Hahmlet|Song Myung|Do Hyeon|Black Han Sans|Orbit|Gasoek|Sunflower|RIDIBatang|KoPub/.test(all)) ok(`${slug} 한글 폰트 지정`);
   else fail(`${slug} 한글 폰트 지정`, "한글 폰트를 명시하지 않아 시스템 기본으로 떨어진다");
 }