style(sw): calmer viewer header switches without the yellow face

User-approved 2026-10-22 design for the SW viewer header switches (2.5D,
어두운 배경); panel switches and the --hm-sw-viewer-accent token unchanged.
- OFF: track #020a07, knob #5f7a71 (dim gray-green).
- ON: track var(--hm-sw-viewer-hover) #266651, knob var(--hm-sw-viewer-muted)
  #bddfd4. No yellow face or ring.
- New tokens --hm-sw-viewer-switch-thumb-off / -on / --hm-sw-viewer-switch-on;
  size, knob travel, bevel and the 60% disabled opacity unchanged.
- DESIGN_RULES.md header switch token row updated.

packages/sw/ai/DESIGN_RULES.md

@@ -144,7 +144,7 @@
 | Header | `--hm-sw-viewer-height` 52px, `--hm-sw-viewer-background` #0a0a0b(단색, 2026-10-21 — Storybook 뷰어 캔버스 바탕색), `--hm-sw-viewer-border-color` #071e18, `--hm-sw-viewer-text` #fff, `--hm-sw-viewer-muted` #bddfd4, `--hm-sw-viewer-accent` #ffc600, `--hm-sw-viewer-hover` #266651 |
 | 로고 면 | `--hm-sw-viewer-brand-width` 72px, `--hm-sw-viewer-brand-empty-width` 24px(로고 없음), `--hm-sw-viewer-brand-top` #123328, `--hm-sw-viewer-brand-middle` #205241, `--hm-sw-viewer-brand-bottom` #071e18 |
 | 크기·글자 | `--hm-sw-viewer-gap` 4px, `--hm-sw-viewer-radius` 4px, `--hm-sw-viewer-control-height` 40px, `--hm-sw-viewer-button-height` 34px, `--hm-sw-viewer-font-size` 14px, `--hm-sw-viewer-label-size` 11px, `--hm-sw-viewer-icon-size` 16px, `--hm-sw-viewer-disabled-opacity` 0.6 |
-| Header 스위치·아이콘 | `--hm-sw-viewer-switch-off` #0a221d, `--hm-sw-viewer-switch-bevel` `inset 0 1px 0 rgba(255, 255, 255, 0.1), inset 0 -1px 1px rgba(0, 0, 0, 0.25)`, `--hm-sw-viewer-icon-outline-color` = `var(--hm-sw-header-text-outline-color)`, `--hm-sw-viewer-icon-outline-width` 1px |
+| Header 스위치·아이콘 | `--hm-sw-viewer-switch-off` #020a07(OFF 트랙), `--hm-sw-viewer-switch-thumb-off` #5f7a71(OFF 원형, 흐린 회녹색), `--hm-sw-viewer-switch-on` = `var(--hm-sw-viewer-hover)`(ON 트랙), `--hm-sw-viewer-switch-thumb-on` = `var(--hm-sw-viewer-muted)`(ON 원형, 민트; 노란색·테두리 없음, 2026-10-22), `--hm-sw-viewer-switch-bevel` `inset 0 1px 0 rgba(255, 255, 255, 0.1), inset 0 -1px 1px rgba(0, 0, 0, 0.25)`, `--hm-sw-viewer-icon-outline-color` = `var(--hm-sw-header-text-outline-color)`, `--hm-sw-viewer-icon-outline-width` 1px |
 | Dropdown·More | `--hm-sw-viewer-menu-background` #fff, `--hm-sw-viewer-menu-border-color` #dedbd2, `--hm-sw-viewer-menu-text` #0a221d, `--hm-sw-viewer-menu-muted` #6e6759, `--hm-sw-viewer-menu-highlight` `rgba(189, 223, 212, 0.45)`, `--hm-sw-viewer-menu-highlight-text` #123328, `--hm-sw-viewer-menu-shadow` `0 0 12px rgba(0, 0, 0, 0.2)`, `--hm-sw-viewer-menu-item-height` 36px, `--hm-sw-viewer-more-background` #f5f0e5, `--hm-sw-viewer-more-border-color` #897445 |
 | 패널 콘텐츠 | `--hm-sw-viewer-panel-background` = `var(--hm-sw-property-surface)`, `--hm-sw-viewer-panel-field-background` = `var(--hm-sw-property-content)`, `--hm-sw-viewer-panel-inner-border` = `var(--hm-sw-property-inner-border)`, `--hm-sw-viewer-panel-text` = `var(--hm-sw-property-label)`, `--hm-sw-viewer-panel-heading` #3e3523, `--hm-sw-viewer-panel-label` #6e6759, `--hm-sw-viewer-panel-primary` #123328, `--hm-sw-viewer-panel-switch-off` = `var(--hm-sw-property-inner-border)`, `--hm-sw-viewer-panel-switch-on` #266651, `--hm-sw-viewer-panel-badge-background` = `var(--hm-sw-property-table)`, `--hm-sw-viewer-panel-overlay` `rgba(0, 0, 0, 0.1)`, `--hm-sw-viewer-panel-spacing` 12px |