feat(search): 站内搜索/RSS/sitemap/Artalk 懒挂载

- astro-pagefind：构建期索引；SearchDialog 首开懒加载 + 200ms 防抖，
  入口=Header 钮 + 键盘 /（P0 键位集补全）
- @astrojs/rss：posts 全量（draft 排除），双语分流留 Phase 3
- @astrojs/sitemap：sitemap-index 产出
- ArtalkComments：IntersectionObserver 进入视口才拉 Artalk.js，
  pageKey=/archives/{slug}/（中英共键，评论不分裂）

验证: pnpm astro build exit 0；dist/pagefind 目录 + rss.xml +
      sitemap-index.xml 三件断言过

Spec: 2026-10-24_add-blog-skeleton
Co-authored-by: GLM-5.3

src/components/ArtalkComments.astro

@@ -0,0 +1,43 @@
+---
+// Artalk 评论挂载（Phase 0 已部署 @ https://wait4x.online/artalk）
+// 懒加载：进入视口才拉 Artalk.js，长文页不为其付首屏成本
+interface Props {
+  pageKey: string;   // 评论流键：中英双语页共用同一 slug（评论不分裂）
+  pageTitle: string;
+}
+const { pageKey, pageTitle } = Astro.props;
+---
+
+<div id="artalk-container" data-page-key={pageKey} data-page-title={pageTitle}></div>
+
+<script>
+  const el = document.getElementById('artalk-container');
+  if (el) {
+    const mount = () => {
+      if (document.getElementById('artalk-lib')) return initArtalk();
+      const s = document.createElement('script');
+      s.id = 'artalk-lib';
+      s.src = 'https://wait4x.online/artalk/dist/Artalk.js';
+      s.onload = initArtalk;
+      document.head.appendChild(s);
+    };
+    const initArtalk = () => {
+      const lib = (window as unknown as { Artalk?: { init: (o: object) => void } }).Artalk;
+      lib?.init({
+        el: '#artalk-container',
+        server: 'https://wait4x.online/artalk',
+        site: 'wait4x',
+        pageKey: el.dataset.pageKey,
+        pageTitle: el.dataset.pageTitle,
+        locale: 'zh-CN',
+      });
+    };
+    // 进入视口 ~200px 前挂载；无 IO 环境直接挂
+    if ('IntersectionObserver' in window) {
+      new IntersectionObserver(
+        (entries, obs) => { if (entries.some((e) => e.isIntersecting)) { obs.disconnect(); mount(); } },
+        { rootMargin: '200px' }
+      ).observe(el);
+    } else mount();
+  }
+</script>

src/components/SearchDialog.astro

@@ -0,0 +1,101 @@
+---
+// 站内搜索（Pagefind）：首次打开才懒加载索引（spectre 模式，见调研报告 §4c）
+// 入口：Header 搜索钮 + 键盘 `/`
+---
+
+<dialog id="search-dialog" class="search-dialog">
+  <input id="search-input" type="search" placeholder="搜索文章…（Esc 关闭）" autocomplete="off" />
+  <ul id="search-results" class="results" aria-live="polite"></ul>
+  <p class="search-hint">索引由 Pagefind 构建期生成 · 静态站零后端</p>
+</dialog>
+
+<script>
+  const dlg = document.getElementById('search-dialog') as HTMLDialogElement;
+  const input = document.getElementById('search-input') as HTMLInputElement;
+  const list = document.getElementById('search-results')!;
+  type PagefindLike = {
+    search: (q: string) => Promise<{ results: { data: () => Promise<{ url: string; excerpt: string; meta: { title: string } }> }[] }>;
+  };
+  let pf: PagefindLike | null = null;
+  let loadStarted = false;
+
+  async function ensureIndex() {
+    if (loadStarted) return;
+    loadStarted = true;
+    pf = (await import(/* @vite-ignore */ '/pagefind/pagefind.js')) as unknown as PagefindLike;
+  }
+
+  function open() {
+    dlg.showModal();
+    input.value = '';
+    list.innerHTML = '';
+    void ensureIndex();
+    input.focus();
+  }
+
+  document.querySelector('[data-search-trigger]')?.addEventListener('click', open);
+  document.addEventListener('keydown', (e) => {
+    const inField = document.activeElement instanceof HTMLElement &&
+      (document.activeElement.tagName === 'INPUT' || document.activeElement.tagName === 'TEXTAREA');
+    if (e.key === '/' && !inField) { e.preventDefault(); open(); }
+  });
+
+  let timer: number | undefined;
+  input.addEventListener('input', () => {
+    clearTimeout(timer);
+    timer = window.setTimeout(async () => {
+      if (!pf) return;
+      const q = input.value.trim();
+      if (!q) { list.innerHTML = ''; return; }
+      const res = await pf.search(q);
+      list.innerHTML = '';
+      for (const r of res.results.slice(0, 8)) {
+        const d = await r.data();
+        const li = document.createElement('li');
+        const a = document.createElement('a');
+        a.href = d.url;
+        a.className = 'tap';
+        a.innerHTML = `<strong>${d.meta.title}</strong><span>${d.excerpt}</span>`;
+        li.appendChild(a);
+        list.appendChild(li);
+      }
+      if (!list.children.length) list.innerHTML = '<li class="empty">无结果</li>';
+    }, 200);
+  });
+</script>
+
+<style>
+  .search-dialog {
+    margin-top: 12vh;
+    width: min(560px, calc(100vw - 32px));
+    border: 1px solid var(--line);
+    border-radius: 10px;
+    background: var(--bg);
+    color: var(--ink-2);
+    padding: var(--space-3);
+  }
+  .search-dialog::backdrop { background: rgba(0, 0, 0, 0.45); }
+  input[type='search'] {
+    width: 100%;
+    padding: var(--space-2) var(--space-3);
+    border: 1px solid var(--line);
+    border-radius: 8px;
+    background: var(--bg-soft);
+    font-size: 15px;
+  }
+  .results { list-style: none; padding: 0; margin: var(--space-2) 0 0; max-height: 50vh; overflow-y: auto; }
+  .results a {
+    display: flex;
+    flex-direction: column;
+    gap: 2px;
+    padding: var(--space-2) var(--space-3);
+    border-radius: 8px;
+    text-decoration: none;
+  }
+  .results a:hover { background: var(--bg-soft); }
+  .results strong { color: var(--ink-1); font-size: 14px; }
+  .results span { font-size: 12px; color: var(--ink-3); }
+  .results a span :global(mark) { background: var(--accent-soft); }
+  .empty { padding: var(--space-3); font-size: 13px; color: var(--ink-3); }
+  .search-hint { margin-top: var(--space-2); font-size: 11px; color: var(--ink-4); text-align: center; font-family: var(--font-mono); }
+</style>

src/layouts/BaseLayout.astro

@@ -12,6 +12,7 @@ import Header from '../components/Header.astro';
 import Footer from '../components/Footer.astro';
 import ThemeScript from '../components/ThemeScript.astro';
 import Keyboard from '../components/geek/Keyboard.astro';
+import SearchDialog from '../components/SearchDialog.astro';
 import BuildInfo from '../components/geek/BuildInfo.astro';
 import { ClientRouter } from 'astro:transitions';
 
@@ -47,5 +48,6 @@ const { title, description = 'wait4x 的博客：阅读 · 技术 · 摄影', tr
       <BuildInfo slot="build-info" />
     </Footer>
     <Keyboard />
+    <SearchDialog />
   </body>
 </html>

src/pages/archives/[...slug].astro

@@ -2,6 +2,7 @@
 import type { CollectionEntry } from 'astro:content';
 import { getCollection, render } from 'astro:content';
 import BaseLayout from '../../layouts/BaseLayout.astro';
+import ArtalkComments from '../../components/ArtalkComments.astro';
 import { trackOf } from '../../content.config';
 
 // URL = /archives/{slug}，slug 即文件名，与 Halo 旧结构 1:1（不可改）
@@ -104,8 +105,7 @@ const toc = headings.filter((h) => h.depth === 2 || h.depth === 3);
     )}
   </nav>
 
-  <!-- T8 填充：在此容器注入 Artalk 脚本，data-page-key 即文章 id -->
-  <div id="artalk-container" data-page-key={entry.id}></div>
+  <ArtalkComments pageKey={`/archives/${entry.id}/`} pageTitle={entry.data.title} />
 </BaseLayout>
 
 <script>

src/pages/rss.xml.ts

@@ -0,0 +1,21 @@
+import rss from '@astrojs/rss';
+import { getCollection } from 'astro:content';
+import type { APIContext } from 'astro';
+
+// RSS：posts 集合全量（draft 排除）；Phase 3 起双语各出一路（/rss.xml 与 /en/rss.xml）
+export async function GET(context: APIContext) {
+  const posts = (await getCollection('posts', ({ data }) => !data.draft))
+    .sort((a, b) => b.data.pubDate.valueOf() - a.data.pubDate.valueOf());
+  return rss({
+    title: 'wait4x',
+    description: '阅读 · 技术 · 摄影',
+    site: context.site ?? 'https://wait4x.online',
+    items: posts.map((p) => ({
+      title: p.data.title,
+      pubDate: p.data.pubDate,
+      description: p.data.tags.join(', '),
+      link: `/archives/${p.id}/`,
+    })),
+    trailingSlash: true,
+  });
+}