Move admin state into AdminPage

All admin state (tab, users, projects, loading/error, preview, reset
result) and the data loader were only used by AdminPage, so they now live
there as local state instead of in App's context. The page loads its data
when it opens (still gated on authUser.isAdmin; the server enforces it too).

Add tests: admin sees users and projects, deleting a user reloads the
list, and non-admins get no Admin button.

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

src/pages/AdminPage.jsx

@@ -1,6 +1,9 @@
+import { useEffect, useState } from 'react';
 import { useApp } from '../context/AppContext.js';
 import { buildExportHtml } from '../utils/bibleUtils.jsx';
 import {
+  adminListUsers,
+  adminListProjects,
   adminDeleteUser,
   adminDeleteProject,
   adminGetProject,
@@ -8,19 +11,33 @@ import {
 } from '../syncService.js';
 
 export default function AdminPage() {
-  const {
-    authUser,
-    authStatus,
-    goHome,
-    adminTab, setAdminTab,
-    adminUsers,
-    adminProjects,
-    adminLoading,
-    adminError,
-    adminViewProject, setAdminViewProject,
-    adminResetResult, setAdminResetResult,
-    loadAdminData,
-  } = useApp();
+  const { authUser, authStatus, goHome } = useApp();
+  const [adminTab, setAdminTab] = useState('users'); // 'users' | 'projects'
+  const [adminUsers, setAdminUsers] = useState([]);
+  const [adminProjects, setAdminProjects] = useState([]);
+  const [adminLoading, setAdminLoading] = useState(false);
+  const [adminError, setAdminError] = useState('');
+  const [adminViewProject, setAdminViewProject] = useState(null); // full project data being previewed
+  const [adminResetResult, setAdminResetResult] = useState(null); // { email, temporaryPassword } shown once
+
+  const loadAdminData = () => {
+    setAdminLoading(true);
+    setAdminError('');
+    Promise.all([adminListUsers(), adminListProjects()]).then(([usersResult, projectsResult]) => {
+      setAdminLoading(false);
+      if (!usersResult.ok || !projectsResult.ok) {
+        setAdminError(usersResult.error ?? projectsResult.error ?? 'Failed to load admin data.');
+        return;
+      }
+      setAdminUsers(usersResult.data);
+      setAdminProjects(projectsResult.data);
+    });
+  };
+
+  useEffect(() => {
+    if (authUser?.isAdmin) loadAdminData();
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [authUser?.isAdmin]);
 
   const handleDeleteUserAdmin = async (id, email) => {
     if (!window.confirm(`Delete account "${email}"? Their projects are kept, not deleted, but become inaccessible until reassigned.`)) return;