style(sw): drop the 취소 / 적용 footer from the viewer options popup

Options already apply on every toggle, input and slider change, so the footer
only recorded an event and closed the popup. The options panel no longer
passes footer (no empty footer area or divider); reset stays in the title bar.
The 축척 지정 input popup keeps its footer. VIEWER.md §4.1, the composition
pattern and Example H follow.

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

@@ -98,8 +98,7 @@ export function ExampleHViewerMode({ onEvent }: { onEvent?: (name: string) => vo
         </SWViewerSection>
       </SWViewerPanel>
 
-      <SWViewerPanel title="옵션" open={panels.options} onClose={() => setPanels({ ...panels, options: false })} width={340} height="auto" inset={{ side: 356 }}
-        footer={<SWViewerButton variant="primary" onClick={() => { onEvent?.("options:apply"); setPanels({ ...panels, options: false }) }}>적용</SWViewerButton>}>
+      <SWViewerPanel title="옵션" open={panels.options} onClose={() => setPanels({ ...panels, options: false })} width={340} height="auto" inset={{ side: 356 }}>
         <SWViewerSection title="표시">
           <SWViewerField label="그리드">{id => <SWViewerSwitch id={id} checked={grid} onCheckedChange={setGrid} />}</SWViewerField>
           <SWViewerField label="줌 속도" layout="stacked" below={<SWViewerSlider aria-label="줌 속도" value={zoomSpeed} min={0.2} max={3} step={0.1} onValueChange={setZoomSpeed} />}>