feat(sw): refine viewer model layout design and theme tokens

- Model / Layout tabs follow Figma 7652:40344: gradient faces, gold / green
  gradient borders, blurred outline, inner shadow and top gloss, with every
  color in its own --hm-sw-viewer-tab(s)-* token (consumer-overridable)
- Box height matches the adjacent field group (42px, from the control height
  token); padding 1px 1px 1.5px, button side padding 5px, 1px right margin
  for a tabs-only first group; 378px max width, equal buttons and the
  measured More steps are unchanged; existing text-shadow kept
- Storybook: SW/Viewer > Model / Layout story (states and token override);
  Logo story listed before Responsive More
- AI docs (VIEWER.md, DESIGN_RULES.md) and viewer / text-weight test
  expectations updated

packages/sw/tests/text-weight.browser.mjs

@@ -152,7 +152,8 @@ const labels = vNames.map(v => v.text)
 check('Viewer: file name, 파일 열기, 전체 보기 · 레이어 · 설정 · 속성, Model · Layout are 14px 700 + 1.3px outline', want.every(w => labels.includes(w)) && labels.some(t => t.startsWith('Model')) && labels.some(t => t.startsWith('Layout')) && vNames.every(v => v.weight === '700' && v.size === '14px' && v.outline === OUTLINE_14), vNames)
 check('Viewer: 샘플 is no longer a header label', !labels.includes('샘플'), labels)
 const counts = await styles('.hm-sw-viewer-header >> nth=0 >> .hm-sw-viewer-header__count')
-check('Viewer: tab counts keep 11px 400', counts.length > 0 && counts.every(c => c.weight === '400' && c.size === '11px'), counts)
+// 2026-10-23 Figma 7652:40344: counts are 14px (the name's size), still 400 with the 1px outline.
+check('Viewer: tab counts 14px 400 (Figma 7652:40344)', counts.length > 0 && counts.every(c => c.weight === '400' && c.size === '14px'), counts)
 // File open button (파일 열기, the logo menu is gone): hover keeps its label in place, size and weight.
 const openButton = vh.locator('[data-document-open]')
 await stableOnHover('Viewer 파일 열기', openButton, openButton.locator('.hm-sw-viewer-header__open-label'))