feat: complete Phase 3 — advanced features for Casera web app

Adds sharing (residence share codes, join, user management, .casera file
export/import), subscription status with feature comparison, notification
preferences with bell icon, profile settings (edit info, change password,
theme picker, delete account), onboarding wizard with create/join paths,
enhanced dashboard with stats cards, Recharts completion chart, recent
activity feed, and task report PDF download.

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

src/lib/hooks/use-auth.ts

@@ -0,0 +1,27 @@
+"use client";
+
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import * as authApi from '@/lib/api/auth';
+import { useRouter } from 'next/navigation';
+
+export function useCurrentUser() {
+  return useQuery({
+    queryKey: ['auth', 'user'],
+    queryFn: () => authApi.getCurrentUser(),
+    retry: false,
+    staleTime: 5 * 60 * 1000, // 5 minutes
+  });
+}
+
+export function useLogout() {
+  const queryClient = useQueryClient();
+  const router = useRouter();
+
+  return useMutation({
+    mutationFn: () => authApi.logout(),
+    onSuccess: () => {
+      queryClient.clear();
+      router.push('/login');
+    },
+  });
+}