style(storybook): refine manager sidebar, LNB inset and shared story frame

- Manager sidebar labels and sort order for the grouped pages; LNB 1-depth
  text start 12px (token, baseline and LNB doc updated)
- Shared story frame: drop the divider under section titles, side margin
  max 60px -> 30px; Foundation color/typography spacing
- Pseudo-state mirroring also pins :focus-visible via data-sb-focus while
  keeping the previous clones for compound rules (Slider Focus + Drag)

src/components/separator.stories.tsx

@@ -21,7 +21,7 @@ export default meta
 type Story = StoryObj<typeof meta>
 
 // Representative-page layout (Storybook presentation only): equal columns on PC (iframe width 1000px and up), fewer below that
-// (240px minimum). Each specimen sits in its own single-column StateBoard (min larger than any column), so every subtitle and divider
+// (240px minimum). Each specimen sits in its own single-column StateBoard (min larger than any column), so every subtitle
 // has the width of its column; a section with fewer specimens than columns leaves the remaining columns empty.
 const specimenColumns = {
   2: "min-[1000px]:grid-cols-2",