Collapse sidebar nav groups into dropdowns that open on the active page

Each group label (Dashboard, Settings) toggles its items; a group starts
closed unless it holds the current route, and a manual toggle resets on
the next navigation. Mobile keeps every item visible.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/components/AppLayout.tsx

@@ -135,6 +135,9 @@ export function AppLayout() {
   const { signOut } = useClerk()
   const { pathname } = useLocation()
   const current = NAV.find(n => pathname.startsWith(n.to))
+  // Nav groups stay closed unless they hold the current page; a click on the label overrides that until the next route.
+  const [toggled, setToggled] = useState<Partial<Record<Key, boolean>>>({})
+  useEffect(() => setToggled({}), [pathname])
   const name = user?.fullName || user?.primaryEmailAddress?.emailAddress || '-'
 
   return (
@@ -143,14 +146,22 @@ export function AppLayout() {
         <NavLink to="/production"><Brand /></NavLink>
         <OrgSwitcher />
         <nav aria-label={t('layout.mainNav')}>
-          {NAV_GROUPS.map(g => [
-            <div key={g.label} className="nav-label">{t(g.label)}</div>,
-            ...g.items.map(n => (
-              <NavLink key={n.to} to={n.to} className={({ isActive }) => (isActive ? 'active' : undefined)}>
-                <Icon name={n.icon} />{t(n.label)}
-              </NavLink>
-            )),
-          ])}
+          {NAV_GROUPS.map(g => {
+            const open = toggled[g.label] ?? g.items.some(n => pathname.startsWith(n.to))
+            return [
+              <button key={g.label} type="button" className="nav-label" aria-expanded={open} aria-controls={`nav-${g.label}`}
+                onClick={() => setToggled(s => ({ ...s, [g.label]: !open }))}>
+                {t(g.label)}<Icon name="chevron-down" />
+              </button>,
+              <div key={`${g.label}-items`} id={`nav-${g.label}`} className={open ? 'nav-items' : 'nav-items closed'}>
+                {g.items.map(n => (
+                  <NavLink key={n.to} to={n.to} className={({ isActive }) => (isActive ? 'active' : undefined)}>
+                    <Icon name={n.icon} />{t(n.label)}
+                  </NavLink>
+                ))}
+              </div>,
+            ]
+          })}
         </nav>
         <div className="sidebar-help">
           <Icon name="info" />