docs(sw): viewer panel 8px bottom edge and header switch checked tokens

- VIEWER.md §4: the panel body bottom edge is an 8px transparent border
  (padding-bottom 0), matching 1c649cc.
- DESIGN_RULES.md §11 state table: a checked header switch uses
  --hm-sw-viewer-switch-on / --hm-sw-viewer-switch-thumb-on (no yellow), as the
  token table and CSS already do.

packages/sw/ai/DESIGN_RULES.md

@@ -154,7 +154,7 @@
 |---|---|---|
 | Hover | 글자·아이콘 `--hm-sw-viewer-accent`(#ffc600), 면 없음, 크기·위치 변화 없음(2026-10-21; 상태 `SWViewerStatus`는 Hover 없음) | `outline` 버튼: 면 `--hm-sw-viewer-panel-field-background` / `primary`: 면·테두리 `--hm-sw-viewer-hover` / `tone="green"`: 면·테두리 `--hm-sw-viewer-hover`, 글자 #fff / `ghost`: 글자만 `--hm-sw-header-selected-color` |
 | Active·Pressed·열림·선택 탭 | 글자·아이콘 `--hm-sw-viewer-accent`(#ffc600), 선택 박스 없음 | `tone="green"` 누르는 동안: 면·테두리 `--hm-sw-viewer-panel-primary`, 글자 #fff |
-| Checked(스위치) | 면 `--hm-sw-viewer-accent`, thumb `--hm-sw-viewer-switch-off` | 면 `--hm-sw-viewer-panel-switch-on` |
+| Checked(스위치) | 면 `--hm-sw-viewer-switch-on`(= `--hm-sw-viewer-hover`), thumb `--hm-sw-viewer-switch-thumb-on`(노란색 없음, 2026-10-22) | 면 `--hm-sw-viewer-panel-switch-on` |
 | Focus | 2px solid `--hm-sw-viewer-accent` 외곽선 | 버튼·Input·Slider: 2px solid `--hm-sw-viewer-panel-switch-on` 외곽선 |
 | Disabled | `--hm-sw-viewer-disabled-opacity`(0.6) | 버튼·Input·Field 0.5 |
 | Dropdown 항목 | 면 `--hm-sw-viewer-menu-highlight`, 글자 `--hm-sw-viewer-menu-highlight-text`(Focus·Hover·서브메뉴 열림), Disabled 0.5 | — |