B7 review-response batch: derived about counter, CJK-aware reading time, ZH copy fixes, hero leads with capability

src/pages/index.astro

@@ -47,9 +47,10 @@ const featuredMetrics: Record<string, string> = {
       <h1>{SITE.author} — full-stack developer &amp; DevOps engineer</h1>
     </div>
     <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.
+      I build and operate production web systems — from the code down to the servers.
+      <strong>162 containers across three self-managed hosts</strong> run client sites, a mail
+      platform, CI/CD, workflow automation and this blog. I write up what broke, what the
+      evidence said, and how I fixed it.
     </p>
     <p class="hero-cta">
       <a class="btn btn-primary" href="#featured">Read the engineering case studies ↓</a>
@@ -72,6 +73,8 @@ const featuredMetrics: Record<string, string> = {
           <div class="bento-visual" aria-hidden="true">
             <img
               src={`/og/thumb/${cleanSlug}-800.webp`}
+              srcset={`/og/thumb/${cleanSlug}-400.webp 400w, /og/thumb/${cleanSlug}-800.webp 800w`}
+              sizes="(max-width: 640px) 60vw, 341px"
               alt=""
               loading="lazy"
               decoding="async"