style(sw): viewer popup typography, 전체 레이어 title and options layout

- Property popup: row labels 14px 500, read-only values 14px in the panel text
  color, monospace removed; 일반 정보 / 기하 속성 groups 20px apart
  (--hm-sw-viewer-panel-spacing on the second section).
- Layer popup: 전체 레이어 is a plain SWViewerSection title (existing
  .hm-sw-viewer-section__title) with the all-layers switch on the same row;
  layer names 14px 500, no monospace.
- Options popup follows the user image: 표시 (LWDISPLAY), 표시 배율 with the
  px/mm unit on the input row, updated lineweight hints.
- Remove stray monospace font-family from SW Story CSS.
- VIEWER.md §4.1 / new §4.2, DESIGN_RULES §11, Example H aligned.

packages/sw/ai/examples/ExampleH-ViewerMode.tsx

@@ -77,7 +77,9 @@ export function ExampleHViewerMode({ onEvent }: { onEvent?: (name: string) => vo
       <SWViewerPanel title="레이어" open={panels.layers} onClose={() => setPanels({ ...panels, layers: false })}>
         <SWViewerSection surface="plain" aria-label="레이어 목록">
           {/* Top: all-layers SWViewerSwitch. Rows: swatch · name · count · bulb button (SWLayerVisibilityIcon), not a switch. */}
-          <SWViewerField label="전체 레이어">{id => <SWViewerSwitch id={id} checked={allVisible} onCheckedChange={setAllLayers} />}</SWViewerField>
+          <SWViewerSection surface="plain" title="전체 레이어" className="app-viewer-all-layers">
+            <SWViewerSwitch aria-label="전체 레이어" checked={allVisible} onCheckedChange={setAllLayers} />
+          </SWViewerSection>
           <ul className="app-viewer-layers">
             {layers.map(layer => {
               const visible = !hiddenLayers.has(layer.name)