feat: Add admin vehicle management and profile vehicles display (refs #11)

- Add GET /api/admin/stats endpoint for Total Vehicles widget
- Add GET /api/admin/users/:auth0Sub/vehicles endpoint for user vehicle list
- Update AdminUsersPage with Total Vehicles stat and expandable vehicle rows
- Add My Vehicles section to SettingsPage (desktop) and MobileSettingsScreen
- Update AdminUsersMobileScreen with stats header and vehicle expansion
- Add defense-in-depth admin checks and error handling
- Update admin README documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/features/admin/api/admin.api.ts

@@ -56,6 +56,23 @@ export interface AuditLogsResponse {
   total: number;
 }
 
+// Admin stats response
+export interface AdminStatsResponse {
+  totalVehicles: number;
+  totalUsers: number;
+}
+
+// User vehicle (admin view)
+export interface AdminUserVehicle {
+  year: number;
+  make: string;
+  model: string;
+}
+
+export interface AdminUserVehiclesResponse {
+  vehicles: AdminUserVehicle[];
+}
+
 // Admin access verification
 export const adminApi = {
   // Verify admin access
@@ -64,6 +81,12 @@ export const adminApi = {
     return response.data;
   },
 
+  // Admin dashboard stats
+  getStats: async (): Promise<AdminStatsResponse> => {
+    const response = await apiClient.get<AdminStatsResponse>('/admin/stats');
+    return response.data;
+  },
+
   // Admin management
   listAdmins: async (): Promise<AdminUser[]> => {
     const response = await apiClient.get<AdminUser[]>('/admin/admins');
@@ -309,6 +332,13 @@ export const adminApi = {
       return response.data;
     },
 
+    getVehicles: async (auth0Sub: string): Promise<AdminUserVehiclesResponse> => {
+      const response = await apiClient.get<AdminUserVehiclesResponse>(
+        `/admin/users/${encodeURIComponent(auth0Sub)}/vehicles`
+      );
+      return response.data;
+    },
+
     updateTier: async (auth0Sub: string, data: UpdateUserTierRequest): Promise<ManagedUser> => {
       const response = await apiClient.patch<ManagedUser>(
         `/admin/users/${encodeURIComponent(auth0Sub)}/tier`,

frontend/src/features/admin/hooks/useUsers.ts

@@ -30,6 +30,12 @@ export const userQueryKeys = {
   all: ['admin-users'] as const,
   list: (params: ListUsersParams) => [...userQueryKeys.all, 'list', params] as const,
   detail: (auth0Sub: string) => [...userQueryKeys.all, 'detail', auth0Sub] as const,
+  vehicles: (auth0Sub: string) => [...userQueryKeys.all, 'vehicles', auth0Sub] as const,
+};
+
+// Query keys for admin stats
+export const adminStatsQueryKeys = {
+  all: ['admin-stats'] as const,
 };
 
 /**
@@ -201,3 +207,36 @@ export const useHardDeleteUser = () => {
     },
   });
 };
+
+/**
+ * Hook to get admin dashboard stats (total vehicles, total users)
+ */
+export const useAdminStats = () => {
+  const { isAuthenticated, isLoading } = useAuth0();
+
+  return useQuery({
+    queryKey: adminStatsQueryKeys.all,
+    queryFn: () => adminApi.getStats(),
+    enabled: isAuthenticated && !isLoading,
+    staleTime: 2 * 60 * 1000, // 2 minutes
+    gcTime: 5 * 60 * 1000, // 5 minutes cache time
+    retry: 1,
+    refetchOnWindowFocus: false,
+  });
+};
+
+/**
+ * Hook to get a user's vehicles (admin view - year, make, model only)
+ */
+export const useUserVehicles = (auth0Sub: string) => {
+  const { isAuthenticated, isLoading } = useAuth0();
+
+  return useQuery({
+    queryKey: userQueryKeys.vehicles(auth0Sub),
+    queryFn: () => adminApi.users.getVehicles(auth0Sub),
+    enabled: isAuthenticated && !isLoading && !!auth0Sub,
+    staleTime: 2 * 60 * 1000,
+    gcTime: 5 * 60 * 1000,
+    retry: 1,
+  });
+};

frontend/src/features/admin/mobile/AdminUsersMobileScreen.tsx

@@ -16,6 +16,8 @@ import {
   useUpdateUserProfile,
   usePromoteToAdmin,
   useHardDeleteUser,
+  useAdminStats,
+  useUserVehicles,
 } from '../hooks/useUsers';
 import {
   ManagedUser,
@@ -82,12 +84,59 @@ const StatusBadge: React.FC<{ active: boolean }> = ({ active }) => (
 );
 
 // Vehicle count badge component
-const VehicleCountBadge: React.FC<{ count: number }> = ({ count }) => (
-  <span className="px-2 py-1 rounded-full text-xs font-medium bg-slate-100 text-slate-700">
+const VehicleCountBadge: React.FC<{ count: number; onClick?: () => void }> = ({ count, onClick }) => (
+  <button
+    onClick={(e) => {
+      e.stopPropagation();
+      onClick?.();
+    }}
+    disabled={count === 0 || !onClick}
+    className={`px-2 py-1 rounded-full text-xs font-medium bg-slate-100 text-slate-700 flex items-center gap-1 ${count > 0 && onClick ? 'cursor-pointer' : ''}`}
+  >
     {count} {count === 1 ? 'vehicle' : 'vehicles'}
-  </span>
+    {count > 0 && onClick && (
+      <svg className="w-3 h-3" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 9l-7 7-7-7" />
+      </svg>
+    )}
+  </button>
 );
 
+// Expandable vehicle list component
+const UserVehiclesList: React.FC<{ auth0Sub: string; isOpen: boolean }> = ({ auth0Sub, isOpen }) => {
+  const { data, isLoading, error } = useUserVehicles(auth0Sub);
+
+  if (!isOpen) return null;
+
+  return (
+    <div className="mt-3 pt-3 border-t border-slate-200 dark:border-silverstone">
+      <p className="text-xs font-semibold text-slate-500 dark:text-silverstone uppercase mb-2 flex items-center gap-1">
+        <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+          <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 4H5c-1.1 0-2 .9-2 2v10c0 1.1.9 2 2 2h4l3 3 3-3h4c1.1 0 2-.9 2-2V6c0-1.1-.9-2-2-2zM8 11V9h8v2m-8 4v-2h5v2" />
+        </svg>
+        Vehicles
+      </p>
+      {isLoading ? (
+        <div className="flex justify-center py-2">
+          <div className="animate-spin rounded-full h-5 w-5 border-b-2 border-blue-600" />
+        </div>
+      ) : error ? (
+        <p className="text-xs text-red-500">Failed to load vehicles</p>
+      ) : !data?.vehicles?.length ? (
+        <p className="text-xs text-slate-400">No vehicles registered</p>
+      ) : (
+        <div className="space-y-1">
+          {data.vehicles.map((vehicle, idx) => (
+            <div key={idx} className="text-sm text-slate-600 dark:text-silverstone bg-slate-50 dark:bg-carbon px-2 py-1 rounded">
+              {vehicle.year} {vehicle.make} {vehicle.model}
+            </div>
+          ))}
+        </div>
+      )}
+    </div>
+  );
+};
+
 export const AdminUsersMobileScreen: React.FC = () => {
   const { isAdmin, loading: adminLoading } = useAdminAccess();
 
@@ -105,6 +154,12 @@ export const AdminUsersMobileScreen: React.FC = () => {
   // Query
   const { data, isLoading, error, refetch } = useUsers(params);
 
+  // Admin stats
+  const { data: statsData } = useAdminStats();
+
+  // Expanded user for vehicle list
+  const [expandedUserId, setExpandedUserId] = useState<string | null>(null);
+
   // Mutations
   const updateTierMutation = useUpdateUserTier();
   const deactivateMutation = useDeactivateUser();
@@ -328,10 +383,17 @@ export const AdminUsersMobileScreen: React.FC = () => {
       <div className="space-y-4 pb-20 p-4">
         {/* Header */}
         <div className="text-center mb-6">
-          <h1 className="text-2xl font-bold text-slate-800">User Management</h1>
-          <p className="text-slate-500 mt-2">
-            {total} user{total !== 1 ? 's' : ''}
-          </p>
+          <h1 className="text-2xl font-bold text-slate-800 dark:text-avus">User Management</h1>
+          <div className="flex justify-center gap-4 mt-3">
+            <div className="bg-blue-50 dark:bg-blue-900/30 px-4 py-2 rounded-lg">
+              <p className="text-xl font-bold text-blue-700 dark:text-blue-400">{statsData?.totalUsers ?? total}</p>
+              <p className="text-xs text-blue-600 dark:text-blue-300">Users</p>
+            </div>
+            <div className="bg-green-50 dark:bg-green-900/30 px-4 py-2 rounded-lg">
+              <p className="text-xl font-bold text-green-700 dark:text-green-400">{statsData?.totalVehicles ?? 0}</p>
+              <p className="text-xs text-green-600 dark:text-green-300">Vehicles</p>
+            </div>
+          </div>
         </div>
 
         {/* Search Bar */}
@@ -454,13 +516,18 @@ export const AdminUsersMobileScreen: React.FC = () => {
                 >
                   <div className="flex items-start justify-between">
                     <div className="flex-1 min-w-0">
-                      <p className="font-medium text-slate-800 truncate">{user.email}</p>
+                      <p className="font-medium text-slate-800 dark:text-avus truncate">{user.email}</p>
                       {user.displayName && (
-                        <p className="text-sm text-slate-500 truncate">{user.displayName}</p>
+                        <p className="text-sm text-slate-500 dark:text-silverstone truncate">{user.displayName}</p>
                       )}
                       <div className="flex flex-wrap gap-2 mt-2">
                         <TierBadge tier={user.subscriptionTier} />
-                        <VehicleCountBadge count={user.vehicleCount} />
+                        <VehicleCountBadge
+                          count={user.vehicleCount}
+                          onClick={user.vehicleCount > 0 ? () => setExpandedUserId(
+                            expandedUserId === user.auth0Sub ? null : user.auth0Sub
+                          ) : undefined}
+                        />
                         <StatusBadge active={!user.deactivatedAt} />
                         {user.isAdmin && (
                           <span className="px-2 py-1 rounded-full text-xs font-medium bg-amber-100 text-amber-700">
@@ -474,6 +541,10 @@ export const AdminUsersMobileScreen: React.FC = () => {
                     </svg>
                   </div>
                 </button>
+                <UserVehiclesList
+                  auth0Sub={user.auth0Sub}
+                  isOpen={expandedUserId === user.auth0Sub}
+                />
               </GlassCard>
             ))}
 

frontend/src/features/settings/mobile/MobileSettingsScreen.tsx

@@ -5,6 +5,7 @@ import { MobileContainer } from '../../../shared-minimal/components/mobile/Mobil
 import { useSettings } from '../hooks/useSettings';
 import { useProfile, useUpdateProfile } from '../hooks/useProfile';
 import { useExportUserData } from '../hooks/useExportUserData';
+import { useVehicles } from '../../vehicles/hooks/useVehicles';
 import { useAdminAccess } from '../../../core/auth/useAdminAccess';
 import { useNavigationStore } from '../../../core/store';
 import { DeleteAccountModal } from './DeleteAccountModal';
@@ -80,6 +81,7 @@ export const MobileSettingsScreen: React.FC = () => {
   const { data: profile, isLoading: profileLoading } = useProfile();
   const updateProfileMutation = useUpdateProfile();
   const exportMutation = useExportUserData();
+  const { data: vehicles, isLoading: vehiclesLoading } = useVehicles();
   const { isAdmin, loading: adminLoading } = useAdminAccess();
   const [showDataExport, setShowDataExport] = useState(false);
   const [showDeleteConfirm, setShowDeleteConfirm] = useState(false);
@@ -316,6 +318,58 @@ export const MobileSettingsScreen: React.FC = () => {
           </div>
         </GlassCard>
 
+        {/* My Vehicles Section */}
+        <GlassCard padding="md">
+          <div>
+            <div className="flex justify-between items-center mb-4">
+              <div className="flex items-center gap-2">
+                <svg className="w-5 h-5 text-primary-500" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                  <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 4H5c-1.1 0-2 .9-2 2v10c0 1.1.9 2 2 2h4l3 3 3-3h4c1.1 0 2-.9 2-2V6c0-1.1-.9-2-2-2zM8 11V9h8v2m-8 4v-2h5v2" />
+                </svg>
+                <h2 className="text-lg font-semibold text-slate-800 dark:text-avus">
+                  My Vehicles
+                </h2>
+                {!vehiclesLoading && vehicles && (
+                  <span className="text-sm text-slate-500 dark:text-titanio">({vehicles.length})</span>
+                )}
+              </div>
+              <button
+                onClick={() => navigateToScreen('Vehicles')}
+                className="px-3 py-1.5 bg-primary-500 text-white rounded-lg text-sm font-medium hover:bg-primary-600 transition-colors dark:bg-primary-600 dark:hover:bg-primary-700"
+                style={{ minHeight: '44px', minWidth: '44px' }}
+              >
+                Manage
+              </button>
+            </div>
+
+            {vehiclesLoading ? (
+              <div className="flex justify-center py-4">
+                <div className="animate-spin rounded-full h-6 w-6 border-b-2 border-primary-500"></div>
+              </div>
+            ) : !vehicles?.length ? (
+              <p className="text-sm text-slate-500 dark:text-titanio py-2">
+                No vehicles registered. Add your first vehicle to get started.
+              </p>
+            ) : (
+              <div className="space-y-2">
+                {vehicles.map((vehicle) => (
+                  <div
+                    key={vehicle.id}
+                    className="p-3 bg-slate-50 dark:bg-nero rounded-lg"
+                  >
+                    <p className="font-medium text-slate-800 dark:text-avus">
+                      {vehicle.year} {vehicle.make} {vehicle.model}
+                    </p>
+                    {vehicle.nickname && (
+                      <p className="text-sm text-slate-500 dark:text-titanio">{vehicle.nickname}</p>
+                    )}
+                  </div>
+                ))}
+              </div>
+            )}
+          </div>
+        </GlassCard>
+
         {/* Notifications Section */}
         <GlassCard padding="md">
           <div>