feat(admin): add the admin users page and view as

src/utils/admin.test.js

@@ -0,0 +1,25 @@
+// @vitest-environment jsdom
+import {describe, expect, it, vi} from 'vitest';
+import {refreshSession} from './api.js';
+import {viewAs} from './admin.js';
+
+describe('viewAs', () => {
+    it('waits for a running refresh before it sends the refresh cookie', async () => {
+        let finishRefresh;
+        globalThis.fetch = vi.fn((url) => (url.endsWith('/api/auth/refresh')
+            ? new Promise((resolve) => {
+                finishRefresh = () => resolve({ok: true, status: 204});
+            })
+            : Promise.resolve({ok: true, status: 204})));
+
+        const refreshing = refreshSession();
+        const switching = viewAs('USER');
+        await Promise.resolve();
+
+        expect(fetch.mock.calls.map(([url]) => url).filter((url) => url.endsWith('/api/auth/view-as'))).toHaveLength(0);
+
+        finishRefresh();
+        await refreshing;
+        await switching;
+    });
+});