docs: 交付文档、维护指引与端到端回归

补齐 README、开发计划、维护交接与 E2E 用例，执行最终验收。

e2e/specs/help-center/publishing.org.spec.ts

@@ -0,0 +1,31 @@
+import { test, expect, createArticle, enableHelpCenter, setArticleStatus, unique } from '@e2e'
+
+// Turning the help center on is an org-wide setting, so this runs in the serial
+// `org` project. The public site is unauthenticated: exactly what is published,
+// nothing else.
+
+test('only published articles are on the public help center @help-center', async ({ adminApi, anonymousPage }) => {
+  const site = await enableHelpCenter(adminApi)
+  const code = unique('HC')
+  const article = await createArticle(adminApi, {
+    question: `How do I reset my router ${code}?`,
+    answer: `Hold the reset button for ten seconds. Reference ${code}.`,
+  })
+  const articleUrl = `${site}/a/${article.slug}`
+
+  // A draft is invisible to the public: not listed, and its URL is not found.
+  await anonymousPage.goto(site)
+  await expect(anonymousPage.getByText(code)).toHaveCount(0)
+  expect((await anonymousPage.request.get(articleUrl)).status()).toBe(404)
+
+  await setArticleStatus(adminApi, article.id, 'published')
+  await anonymousPage.goto(articleUrl)
+  await expect(anonymousPage.getByRole('heading', { name: `How do I reset my router ${code}?` })).toBeVisible()
+  await expect(anonymousPage.getByText('Hold the reset button for ten seconds.')).toBeVisible()
+  await anonymousPage.goto(site)
+  await expect(anonymousPage.getByText(`How do I reset my router ${code}?`)).toBeVisible()
+
+  // Unpublishing takes it down again.
+  await setArticleStatus(adminApi, article.id, 'draft')
+  expect((await anonymousPage.request.get(articleUrl)).status()).toBe(404)
+})