docs: vendor the documentation site into the monorepo

Fold the standalone 3x-ui-docs project (Next.js 16 + Fumadocs, deployed to
docs.sanaei.dev) into docs/ so the panel and its documentation share a single
source of truth, the way sing-box keeps its docs in-tree. The old repo becomes
redundant and can be retired.

- Import the full site under docs/ (app, components, content, lib, public,
  scripts, config). The self-contained pnpm project sits alongside the existing
  engineering notes with no filename collisions.
- Re-point "Edit on GitHub" links from MHSanaei/3x-ui-docs to this repo's
  docs/content/docs path (docs/lib/shared.ts, docs/app/.../page.tsx).
- Add docs-ci.yml and docs-deploy.yml under .github/workflows/, scoped to
  docs/** and run with working-directory: docs, since GitHub only runs
  workflows from the repo-root .github/. deploy-static.yml's GitHub Pages
  publish (CNAME docs.sanaei.dev) carries over unchanged.

Follow-up (outside this commit): attach the docs.sanaei.dev custom domain to
this repository's Pages (or set the Vercel project's root directory to docs),
confirm the site is live from the monorepo, then delete MHSanaei/3x-ui-docs.

docs/app/[lang]/(home)/layout.tsx

@@ -0,0 +1,28 @@
+import { HomeLayout } from 'fumadocs-ui/layouts/home';
+import { baseOptions } from '@/lib/layout.shared';
+import { HomeLanguageSwitcher } from '@/components/home/language-switcher';
+
+export default async function Layout({ params, children }: LayoutProps<'/[lang]'>) {
+  const { lang } = await params;
+  const options = baseOptions(lang);
+  return (
+    <HomeLayout
+      {...options}
+      // Disable fumadocs' built-in popover language switcher here: nested in the
+      // home navbar's Radix NavigationMenu its item clicks don't fire. We inject
+      // an anchor-based one instead (see HomeLanguageSwitcher). Docs keep the
+      // built-in switcher (its sidebar isn't a NavigationMenu, so it works).
+      i18n={false}
+      links={[
+        ...(options.links ?? []),
+        {
+          type: 'custom',
+          secondary: true,
+          children: <HomeLanguageSwitcher current={lang} />,
+        },
+      ]}
+    >
+      {children}
+    </HomeLayout>
+  );
+}

docs/app/[lang]/(home)/page.tsx

@@ -0,0 +1,143 @@
+import Link from 'next/link';
+import { ArrowRight, BookOpen, Heart } from 'lucide-react';
+import { GitHubIcon, TelegramIcon } from '@/components/icons';
+import { Logo } from '@/components/logo';
+import { Features } from '@/components/home/features';
+import { GitHubStatsRow } from '@/components/home/github-stats';
+import { InstallCommand } from '@/components/home/install-command';
+import { getGitHubStats } from '@/lib/github-stats';
+import { i18n } from '@/lib/i18n';
+import { appName, productRepoUrl, deepWikiUrl, telegramChannelUrl, donateUrl } from '@/lib/shared';
+import { getSiteMessages, type SiteMessages } from '@/lib/site-i18n';
+
+export function generateStaticParams() {
+  return i18n.languages.map((lang) => ({ lang }));
+}
+
+const INSTALL_COMMAND =
+  'bash <(curl -Ls https://raw.githubusercontent.com/mhsanaei/3x-ui/master/install.sh)';
+
+export default async function HomePage({ params }: PageProps<'/[lang]'>) {
+  const { lang } = await params;
+  const prefix = lang === 'en' ? '' : `/${lang}`;
+  const m = getSiteMessages(lang);
+  const stats = await getGitHubStats();
+
+  return (
+    <main className="flex flex-1 flex-col">
+      {/* Hero */}
+      <section className="relative overflow-hidden border-b">
+        <div
+          className="pointer-events-none absolute inset-x-0 -top-40 h-80 bg-gradient-to-b from-brand/15 to-transparent blur-3xl"
+          aria-hidden
+        />
+        <div className="mx-auto flex w-full max-w-5xl flex-col items-center px-4 py-20 text-center sm:py-28">
+          <Logo className="h-20 drop-shadow-sm" />
+          <h1 className="mt-6 text-4xl font-bold tracking-tight sm:text-6xl">
+            <span className="bg-gradient-to-r from-cyan-500 to-sky-600 bg-clip-text text-transparent dark:from-cyan-300 dark:to-sky-400">
+              {appName}
+            </span>
+          </h1>
+          <p className="mt-4 max-w-2xl text-lg text-fd-muted-foreground sm:text-xl">{m.tagline}</p>
+
+          <div className="mt-8 flex flex-col items-center gap-3 sm:flex-row">
+            <Link
+              href={`${prefix}/docs`}
+              className="inline-flex items-center gap-2 rounded-xl bg-fd-primary px-5 py-3 font-medium text-fd-primary-foreground transition-opacity hover:opacity-90"
+            >
+              {m.getStarted}
+              <ArrowRight className="size-4 rtl:rotate-180" aria-hidden />
+            </Link>
+            <a
+              href={productRepoUrl}
+              target="_blank"
+              rel="noreferrer noopener"
+              className="inline-flex items-center gap-2 rounded-xl border px-5 py-3 font-medium transition-colors hover:bg-fd-accent hover:text-fd-accent-foreground"
+            >
+              <GitHubIcon className="size-4" />
+              {m.viewOnGitHub}
+            </a>
+          </div>
+
+          <InstallCommand
+            command={INSTALL_COMMAND}
+            copyLabel={m.copyCommand}
+            copiedLabel={m.copied}
+            className="mt-8 w-full max-w-2xl"
+          />
+
+          {/* Build-time stats as the initial render; refreshed live on the client. */}
+          <GitHubStatsRow
+            initial={stats}
+            labels={{ stars: m.stars, forks: m.forks, latest: m.latest }}
+          />
+        </div>
+      </section>
+
+      <Features heading={m.featuresHeading} subtitle={m.featuresSubtitle} items={m.features} />
+
+      <Footer prefix={prefix} m={m} />
+    </main>
+  );
+}
+
+function Footer({ prefix, m }: { prefix: string; m: SiteMessages }) {
+  return (
+    <footer className="border-t">
+      <div className="mx-auto flex w-full max-w-6xl flex-col items-center justify-between gap-4 px-4 py-8 text-sm text-fd-muted-foreground sm:flex-row">
+        <div className="inline-flex items-center gap-2">
+          <Logo className="h-6" />
+          <span>
+            {appName} — {m.licenseBefore}
+            <a
+              href={`${productRepoUrl}/blob/main/LICENSE`}
+              className="underline hover:text-fd-foreground"
+            >
+              GPL-3.0
+            </a>
+            {m.licenseAfter}
+          </span>
+        </div>
+        <nav className="flex items-center gap-4">
+          <Link href={`${prefix}/docs`} className="hover:text-fd-foreground">
+            {m.docs}
+          </Link>
+          <a
+            href={productRepoUrl}
+            className="inline-flex items-center gap-1.5 hover:text-fd-foreground"
+          >
+            <GitHubIcon className="size-4" />
+            GitHub
+          </a>
+          <a
+            href={deepWikiUrl}
+            target="_blank"
+            rel="noreferrer noopener"
+            className="inline-flex items-center gap-1.5 hover:text-fd-foreground"
+          >
+            <BookOpen className="size-4" />
+            DeepWiki
+          </a>
+          <a
+            href={telegramChannelUrl}
+            target="_blank"
+            rel="noreferrer noopener"
+            className="inline-flex items-center gap-1.5 hover:text-fd-foreground"
+          >
+            <TelegramIcon className="size-4" />
+            Telegram
+          </a>
+          <a
+            href={donateUrl}
+            target="_blank"
+            rel="noreferrer noopener"
+            className="inline-flex items-center gap-1.5 hover:text-fd-foreground"
+          >
+            <Heart className="size-4" />
+            {m.donate}
+          </a>
+        </nav>
+      </div>
+    </footer>
+  );
+}

docs/app/[lang]/docs/[[...slug]]/page.tsx

@@ -0,0 +1,80 @@
+import { getPageImage, getPageMarkdownUrl, source } from '@/lib/source';
+import {
+  DocsBody,
+  DocsDescription,
+  DocsPage,
+  DocsTitle,
+  MarkdownCopyButton,
+  ViewOptionsPopover,
+} from 'fumadocs-ui/layouts/docs/page';
+import { notFound } from 'next/navigation';
+import { getMDXComponents } from '@/components/mdx';
+import { OpenAPIPage as BaseOpenAPIPage } from '@/components/openapi-page';
+import { openapi } from '@/lib/openapi';
+import type { Metadata } from 'next';
+import type { ComponentProps } from 'react';
+import { createRelativeLink } from 'fumadocs-ui/mdx';
+import { gitConfig } from '@/lib/shared';
+
+export default async function Page(props: PageProps<'/[lang]/docs/[[...slug]]'>) {
+  const { lang, slug } = await props.params;
+  const page = source.getPage(slug, lang);
+  if (!page) notFound();
+
+  const MDX = page.data.body;
+  const markdownUrl = getPageMarkdownUrl(page).url;
+  const editUrl = `https://github.com/${gitConfig.user}/${gitConfig.repo}/blob/${gitConfig.branch}/${gitConfig.docsDir}/${page.path}`;
+
+  // Generated API reference pages carry `_openapi` metadata. Preload the spec
+  // on the server (highlighting included) so the client OpenAPIPage doesn't have
+  // to load it at render time.
+  const isOpenAPI = Boolean((page.data as { _openapi?: unknown })._openapi);
+  const extraComponents: Record<string, unknown> = {};
+  if (isOpenAPI) {
+    const preloaded = await openapi.preloadOpenAPIPage(page);
+    function PreloadedOpenAPIPage(p: ComponentProps<typeof BaseOpenAPIPage>) {
+      return <BaseOpenAPIPage {...p} {...preloaded} />;
+    }
+    extraComponents.OpenAPIPage = PreloadedOpenAPIPage;
+  }
+
+  return (
+    <DocsPage toc={page.data.toc} full={page.data.full}>
+      <DocsTitle>{page.data.title}</DocsTitle>
+      <DocsDescription className="mb-0">{page.data.description}</DocsDescription>
+      <div className="flex flex-row items-center gap-2 border-b pb-6">
+        <MarkdownCopyButton markdownUrl={markdownUrl} />
+        <ViewOptionsPopover markdownUrl={markdownUrl} githubUrl={editUrl} />
+      </div>
+      <DocsBody>
+        <MDX
+          components={getMDXComponents({
+            // allows linking to other pages with relative file paths
+            a: createRelativeLink(source, page),
+            ...extraComponents,
+          })}
+        />
+      </DocsBody>
+    </DocsPage>
+  );
+}
+
+export async function generateStaticParams() {
+  return source.generateParams();
+}
+
+export async function generateMetadata(
+  props: PageProps<'/[lang]/docs/[[...slug]]'>,
+): Promise<Metadata> {
+  const { lang, slug } = await props.params;
+  const page = source.getPage(slug, lang);
+  if (!page) notFound();
+
+  return {
+    title: page.data.title,
+    description: page.data.description,
+    openGraph: {
+      images: getPageImage(page).url,
+    },
+  };
+}

docs/app/[lang]/docs/layout.tsx

@@ -0,0 +1,12 @@
+import { source } from '@/lib/source';
+import { DocsLayout } from 'fumadocs-ui/layouts/docs';
+import { baseOptions } from '@/lib/layout.shared';
+
+export default async function Layout({ params, children }: LayoutProps<'/[lang]/docs'>) {
+  const { lang } = await params;
+  return (
+    <DocsLayout tree={source.getPageTree(lang)} {...baseOptions(lang)}>
+      {children}
+    </DocsLayout>
+  );
+}

docs/app/[lang]/layout.tsx

@@ -0,0 +1,30 @@
+import '../global.css';
+import { RootProvider } from 'fumadocs-ui/provider/next';
+import { Inter, Vazirmatn } from 'next/font/google';
+import { i18n, localeDirection } from '@/lib/i18n';
+import { provider } from '@/lib/i18n-ui';
+import SearchDialog from '@/components/search-dialog';
+
+const inter = Inter({ subsets: ['latin'], display: 'swap' });
+// Persian UI font; covers Arabic + Latin glyphs so mixed content renders well.
+const vazirmatn = Vazirmatn({ subsets: ['arabic'], display: 'swap' });
+
+export function generateStaticParams() {
+  return i18n.languages.map((lang) => ({ lang }));
+}
+
+export default async function LangLayout({ params, children }: LayoutProps<'/[lang]'>) {
+  const { lang } = await params;
+  const dir = localeDirection(lang);
+  const fontClassName = lang === 'fa' ? vazirmatn.className : inter.className;
+
+  return (
+    <html lang={lang} dir={dir} className={fontClassName} suppressHydrationWarning>
+      <body className="flex min-h-screen flex-col" suppressHydrationWarning>
+        <RootProvider i18n={provider(lang)} search={{ SearchDialog }}>
+          {children}
+        </RootProvider>
+      </body>
+    </html>
+  );
+}