feat: add feedback route, sidebar nav item, and account link card

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/router.tsx

@@ -30,6 +30,7 @@ const SessionDetailPage = lazy(() => import('@/pages/SessionDetailPage'))
 const MySharesPage = lazy(() => import('@/pages/MySharesPage'))
 const TeamAnalyticsPage = lazy(() => import('@/pages/TeamAnalyticsPage'))
 const MyAnalyticsPage = lazy(() => import('@/pages/MyAnalyticsPage'))
+const FeedbackPage = lazy(() => import('@/pages/FeedbackPage'))
 const AccountSettingsPage = lazy(() => import('@/pages/AccountSettingsPage'))
 // Admin pages
 const AdminLayout = lazy(() => import('@/components/admin/AdminLayout'))
@@ -226,6 +227,14 @@ export const router = createBrowserRouter([
           </Suspense>
         ),
       },
+      {
+        path: 'feedback',
+        element: (
+          <Suspense fallback={<PageLoader />}>
+            <FeedbackPage />
+          </Suspense>
+        ),
+      },
       // Admin routes
       {
         path: 'admin',