docs(layout): annotate the sidebar-nav grouped-navigation example as NavGroup[]

.changeset/6131-sidebar-nav-navgroup-annotation.md

@@ -0,0 +1,36 @@
+---
+---
+
+Docs only, publishes nothing: the "Complete Example" block in
+`content/docs/layout/sidebar-nav.mdx` now annotates its grouped-navigation array as
+`NavGroup[]`, importing the type in the same block (objectui#6131).
+
+Without the annotation the array's `badgeVariant: 'destructive'` widens to `string`,
+and `SidebarNav`'s declared `badgeVariant?: 'default' | 'destructive' | 'outline'`
+does not accept it — so the whole array fails to assign to
+`items: NavItem[] | NavGroup[]`. TypeScript then reports the union's *other* branch,
+which is why the message reads "missing the following properties from type 'NavItem':
+title, href" and looks at first like a wrong data shape. The data shape was always
+right; the annotation was missing. A reader who copies this block into an annotated
+position, or assigns it anywhere typed under `strict`, hits the same TS2322.
+
+Measured on this branch against the built `dist/*.d.ts`, with the block temporarily
+re-fenced as `ts` under an `EXIT` trap so it joins the compile population (the fence
+itself belongs to objectui#5867's lane and is deliberately left as `plaintext` here):
+
+- before the annotation, `Semantic phase: 224 of 224 block(s) judged, 1 failed`, gate
+ exit 1, on `content/docs/layout/sidebar-nav.mdx:235:7 TS2322`;
+- after it, `Semantic phase: 224 of 224 block(s) judged, 0 failed`, gate exit 0.
+
+Removing the annotation again reproduces the identical TS2322, so it is load-bearing
+rather than decorative. Declared fragment count is unmoved at 111, no
+`FRAGMENT_MARKER` is added, and the covered/ungated sets are untouched.
+
+The annotation is written so that it **resolves**: the type is imported in the same
+block, because every block compiles in isolation. An annotation naming a type the
+block cannot see errors on the annotation itself, at which point TypeScript stops
+checking the literal underneath and the TS2322 disappears — the false-green shape
+already recorded for `guide/theming` in `scripts/check-doc-snippet-types.mjs`.
+
+This clears the last `content/docs/layout` block that stays red for a reason of its
+own, so the layout group is type-clean ahead of objectui#5867 re-fencing it.

content/docs/layout/sidebar-nav.mdx

@@ -189,7 +189,7 @@ Set a custom title for the sidebar:
 ## Complete Example
 
 ```plaintext
-import { SidebarNav } from '@object-ui/layout';
+import { SidebarNav, type NavGroup } from '@object-ui/layout';
 import { 
  Home,
  Users,
@@ -200,7 +200,7 @@ import {
  Mail
 } from 'lucide-react';
 
-const navigationItems = [
+const navigationItems: NavGroup[] = [
  {
  label: 'Workspace',
  items: [