feat: add About Me dialog showing user info, roles, and groups

- Add GET /api/v1/auth/me endpoint returning current user's UserDetail
- Add AboutMeDialog component with role badges and group memberships
- Add userMenuItems prop to TopBar via design-system update
- Wire "About Me" menu item into user dropdown above Logout

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/components/LayoutShell.tsx

@@ -15,9 +15,10 @@ import {
   useGlobalFilters,
   useStarred,
 } from '@cameleer/design-system';
-import type { SearchResult, SidebarTreeNode } from '@cameleer/design-system';
+import type { SearchResult, SidebarTreeNode, DropdownItem } from '@cameleer/design-system';
 import sidebarLogo from '@cameleer/design-system/assets/cameleer3-logo.svg';
-import { Box, Settings, FileText, ChevronRight, Square, Pause, Star, X } from 'lucide-react';
+import { Box, Settings, FileText, ChevronRight, Square, Pause, Star, X, User } from 'lucide-react';
+import { AboutMeDialog } from './AboutMeDialog';
 import css from './LayoutShell.module.css';
 import { useQueryClient } from '@tanstack/react-query';
 import { useRouteCatalog } from '../api/queries/catalog';
@@ -437,6 +438,12 @@ function LayoutContent() {
 
   const effectiveSelectedPath = sidebarRevealPath ?? location.pathname;
 
+  // --- About Me dialog -----------------------------------------------
+  const [aboutMeOpen, setAboutMeOpen] = useState(false);
+  const userMenuItems: DropdownItem[] = useMemo(() => [
+    { label: 'About Me', icon: createElement(User, { size: 14 }), onClick: () => setAboutMeOpen(true) },
+  ], []);
+
   // --- Exchange full-text search via command palette -----------------
   const [paletteQuery, setPaletteQuery] = useState('');
   const debouncedQuery = useDebouncedValue(paletteQuery, 300);
@@ -724,8 +731,10 @@ function LayoutContent() {
           />
         }
         user={username ? { name: username } : undefined}
+        userMenuItems={userMenuItems}
         onLogout={handleLogout}
       />
+      <AboutMeDialog open={aboutMeOpen} onClose={() => setAboutMeOpen(false)} />
       <CommandPalette
         key={isAdminPage ? 'admin' : 'ops'}
         open={paletteOpen}