style(frontend): 对齐 Alright 主题并接入离线字体

- 主题色板、圆角、阴影与 0.3s 缓动对齐参考站点，布局与尺寸不变
- index.html 预加载本地字体，index.css 定义 LXGW WenKai / Outfit-Medium
- 新增断网渲染端到端用例与 ADR-0006

frontend/e2e/dashboard.spec.ts

@@ -221,3 +221,41 @@ test('cancels a running task from the log drawer', async ({
   await drawer.getByRole('button', { name: '取消运行' }).click()
   await expect(drawer.locator('.status-cancelled').first()).toBeVisible()
 })
+
+test('renders fully offline with bundled fonts', async ({ page }) => {
+  const blocked: string[] = []
+  await page.route('**/*', (route) => {
+    const url = route.request().url()
+    const isLocal =
+      url.startsWith('http://127.0.0.1:5173') ||
+      url.startsWith('http://localhost:5173') ||
+      url.startsWith('data:') ||
+      url.startsWith('blob:')
+    if (isLocal) {
+      return route.continue()
+    }
+    blocked.push(url)
+    return route.abort()
+  })
+
+  await page.goto('/')
+  await expect(page.getByRole('heading', { name: 'TaskPilot' })).toBeVisible()
+
+  const fonts = await page.evaluate(async () => {
+    await document.fonts.ready
+    return {
+      wenkai: document.fonts.check('14px "LXGW WenKai"'),
+      display: document.fonts.check('500 26px "Outfit-Medium"'),
+      loaded: Array.from(document.fonts).map((face) => face.family),
+    }
+  })
+
+  expect(blocked).toEqual([])
+  expect(fonts.wenkai).toBe(true)
+  expect(fonts.display).toBe(true)
+  expect(fonts.loaded).toContain('LXGW WenKai')
+  await page.screenshot({
+    path: 'test-results/dashboard-offline.png',
+    fullPage: true,
+  })
+})