feat(structure): compact archive + tag pages + hero/featured, and fix site search

Found a real bug while verifying the nav search: /pagefind/pagefind.js is an ES
module that defines no window.Pagefind, but Search.astro loaded it with a classic
<script src> and read window.Pagefind — so every query answered "Search is
unavailable." (confirmed live before the fix). Now a dynamic import; the specifier
must be a variable or Rollup resolves it at build time and the build fails.

Measured before/after in a real browser:

- archive /posts/ + /zh/posts/: 18,220px -> 3,788px (71 rows at 44px, grouped by
  year) with a client-side filter (title/tags/description text, category chips,
  14 tag chips, zero requests). Tested: "nginx" -> 6 rows, chip devops -> 28.
- tag pages for tags with >= 3 posts. Measured 235 distinct tags (an earlier brief
  claimed 74), 156 used exactly once — pages only where a topic exists: 40 tags ->
  80 pages, build 165 -> 245 pages. Pills link only when a page exists.
- homepage + ZH homepage: hero (288px) with the real scale claim, three CTAs, a
  fixed Featured 4 (scale -> automation -> observability -> a delivered result),
  Latest 10 -> 6. ZH hero had linked "关于我" to the English /about/.
- long code blocks collapse above 420px with an Expand button + gradient, copy
  button still copies the whole block (verified on the 1010px block).
- search is visible ("⌕ Search /" pill, "/" plus the existing Ctrl/Cmd+K) and the
  zero-result screen offers topic chips instead of a dead end.

Docs: project-state B3 entry, ops-runbook Pagefind gotcha.

src/pages/index.astro

@@ -7,24 +7,51 @@ import { SITE } from '../config';
 import { sortForListing } from '../lib/sort';
 
 const posts = sortForListing(await getCollection('posts', isEn));
+
+// Featured picks: fixed slugs, not "newest 4", so the front page stays stable after a
+// publish and keeps answering "who is this and what has he actually run" (scale →
+// automation → observability → a delivered business result). Falls back to the newest
+// posts if a slug ever disappears.
+const FEATURED_SLUGS = [
+  'running-production-infrastructure-solo',
+  'loop-engineering-without-a-coding-agent',
+  'one-prometheus-for-unraid-synology-and-a-vps',
+  'self-healing-digital-goods-entitlements',
+];
+const bySlug = new Map(posts.map((p) => [p.slug, p]));
+const featured = FEATURED_SLUGS.map((s) => bySlug.get(s)).filter(Boolean);
+const featuredPosts = featured.length === 4 ? featured : posts.slice(0, 4);
 ---
 
 <BaseLayout title={SITE.title} description={SITE.description} altLocaleUrl={`${SITE.url}/zh/`}>
-  <section>
-    <h1>Hi, I'm {SITE.author}.</h1>
-    <p>
-      A full-stack developer and DevOps engineer based in Malaysia. I build web
-      apps (PHP/CodeIgniter, Java/Spring, TypeScript/React), self-host a
-      ~140-container homelab, and run a website design & development business
-      for Malaysian SMEs. I write here about what I learn and ship.
+  <section class="hero">
+    <h1>{SITE.author} — full-stack developer &amp; DevOps engineer</h1>
+    <p class="hero-sub">
+      I run <strong>162 containers across three self-managed hosts</strong> — client sites, a
+      mail platform, CI/CD, workflow automation and this blog — and I build web systems for
+      Malaysian SMEs. I write up what broke, what the evidence said, and how I fixed it.
     </p>
-    <p>
-      <a href="/about/">More about me</a>
-      <span class="sep">·</span>
-      <a href="/posts/">Browse all posts</a>
-      <span class="sep">·</span>
-      <a href="/rss.xml">RSS</a>
+    <p class="hero-cta">
+      <a class="btn btn-primary" href="#featured">Read the engineering case studies ↓</a>
+      <a class="btn" href="/about/">Hiring? Profile &amp; stack →</a>
+      <a class="btn" href={SITE.website} target="_blank" rel="noopener">Malaysian SME? How I work ↗</a>
     </p>
+    <p class="hero-note">
+      {posts.length} posts in English and 中文 · <a href="/rss.xml">RSS</a>
+    </p>
+  </section>
+
+  <section id="featured">
+    <h2>Featured</h2>
+    <div class="featured-grid">
+      {featuredPosts.map((p) => (
+        <a class="featured-card" href={`/posts/${p.slug}/`}>
+          <span class="featured-badge">{p.data.category}</span>
+          <h3>{p.data.title}</h3>
+          <p>{p.data.description}</p>
+        </a>
+      ))}
+    </div>
   </section>
 
   <section>
@@ -32,7 +59,8 @@ const posts = sortForListing(await getCollection('posts', isEn));
     {posts.length === 0 ? (
       <p><em>No posts yet — check back soon.</em></p>
     ) : (
-      <PostList posts={posts} limit={10} />
+      <PostList posts={posts} limit={6} />
     )}
+    <p class="archive-meta"><a href="/posts/">All {posts.length} posts</a> · <a href="/tags/docker/">tag pages</a></p>
   </section>
 </BaseLayout>