feat(ui): standardize LNB sizing and active depth effect

- Adopt the official LNB desktop spec as package defaults: 240px column,
  14px menu text, 48px 1-depth rows and 42px 2/3-depth rows, with new
  item/subitem padding-block and profile min-height tokens.
- Match --hm-lnb-current-depth to the Storybook Manager selected item:
  sampled soft inset falloff (left/top/bottom) and a fade over the last
  quarter, keeping the concave corners and content join.
- Drop the size overrides from the LNB Story CSS and update the LNB, GNB
  and Dashboard docs, AI guides and the theme verification baseline.

src/patterns/lnb.stories.tsx

@@ -34,9 +34,10 @@ import { StateBoard } from "@/components/story-board"
 import { StoryPage, StoryPageHeader, StorySection } from "@/components/story-page"
 import "./lnb.stories.css"
 
-// LNB is a composition pattern. Layout visual reference is the ui-viz LNB (the shared package default: 272px green column, 18/700 items,
-// Beige current item joined to the content, Black 10% hover, Black 8% open group). This Story overrides only the display values (240px column,
-// 212px min width, 14px items, 48/42px rows) in lnb.stories.css; the package defaults are unchanged. The menu data and the current location are local sample data for this Story
+// LNB is a composition pattern. Layout visual reference is the ui-viz LNB (the shared package default: 240px green column, 14/700 items,
+// 48px 1-depth and 42px 2/3-depth rows, Beige current item joined to the content, Black 10% hover, Black 8% open group). The sizes come from the package
+// (`--hm-lnb-*` in packages/ui/src/theme/lnb.css); lnb.stories.css only keeps Story presentation (212px min width, brand bottom padding, profile text,
+// divider lines). The menu data and the current location are local sample data for this Story
 // (no router). The content next to the column is a positioned surface with `--hm-lnb-join` rounded left corners: the LNB Mode page
 // owns it, here it only shows the connection. The column is desktop only (hidden below 1024px).
 
@@ -619,7 +620,7 @@ const mobileViewport = {
   globals: { viewport: { value: "hmMobile", isRotated: false } },
 }
 
-// `hm-lnb-story` (display: contents, see lnb.stories.css) scopes the 212px min width and 14px menu font to this Story only.
+// `hm-lnb-story` (display: contents, see lnb.stories.css) scopes the 212px min width, brand bottom padding, profile text and divider lines to this Story only.
 const meta = { title: "Patterns/Layout/LNB", component: LNB, decorators: [(Story) => <div className="hm-lnb-story"><Story /></div>], parameters: { layout: "fullscreen", controls: { disable: true } } } satisfies Meta<typeof LNB>
 export default meta
 type Story = StoryObj<typeof meta>