fix: prevent Admin password dialog flash (#1134)

* fix: wait for admin access settings before rendering

* test: use frontend route for admin loading check

* test: always release delayed admin settings request

* test: track Admin password dialog during loading

e2e/tests/browser/admin-auth-loading.spec.ts

@@ -0,0 +1,56 @@
+import { expect, test } from '@playwright/test';
+
+import { FRONTEND_URL } from '../../fixtures/test-helpers';
+
+test('waits for access settings before showing the Admin password dialog', async ({ page }) => {
+  await page.addInitScript(() => {
+    const testWindow = window as Window & { __adminPasswordRendered?: boolean };
+    testWindow.__adminPasswordRendered = false;
+
+    const detectAdminPassword = () => {
+      const textNodes = document.createTreeWalker(document, NodeFilter.SHOW_TEXT);
+      while (textNodes.nextNode()) {
+        if (textNodes.currentNode.textContent?.trim() === '管理员密码') {
+          testWindow.__adminPasswordRendered = true;
+          return;
+        }
+      }
+    };
+
+    new MutationObserver(detectAdminPassword).observe(document, {
+      childList: true,
+      subtree: true,
+      characterData: true,
+    });
+  });
+
+  let releaseSettings!: () => void;
+  const settingsPending = new Promise<void>((resolve) => {
+    releaseSettings = resolve;
+  });
+  let markSettingsRequested!: () => void;
+  const settingsRequested = new Promise<void>((resolve) => {
+    markSettingsRequested = resolve;
+  });
+
+  await page.route('**/open_api/settings', async (route) => {
+    markSettingsRequested();
+    await settingsPending;
+    await route.continue();
+  });
+
+  await page.goto(`${FRONTEND_URL}/zh/admin`);
+  await settingsRequested;
+
+  try {
+    await expect(page.getByText('管理员密码', { exact: true })).toHaveCount(0);
+  } finally {
+    releaseSettings();
+  }
+
+  await expect(page.getByText('快速设置', { exact: true })).toBeVisible();
+  await expect(page.getByText('管理员密码', { exact: true })).toHaveCount(0);
+  expect(await page.evaluate(() => (
+    window as Window & { __adminPasswordRendered?: boolean }
+  ).__adminPasswordRendered)).toBe(false);
+});