feat: major content & layout overhaul across all sections

- Problem strip: 4 sign cards with closing statement
- Dataroot section: rebranded as case study with new content
- Services: 2×2 content-rich cards with bullet lists, updated copy
- Process: moved above portfolio, new strategy-focused copy
- Portfolio: 9 items with correct tags, uniform cards, light theme
- SEO: OG tags, canonical, favicons, robots.txt, sitemap, 404
- Backdrop: lighter white for lead panel readability
- Footer, LegalPages component, various text refinements
- Fix CSS syntax error in neural hero hover state

src/pages/blog/[slug].astro

@@ -23,18 +23,18 @@ const formattedDate = new Intl.DateTimeFormat('th-TH', {
   <article class="blog-article">
     <header class="blog-article-hero scene scene-light" data-scene="light">
       <div class="blog-article-heading">
-        <a class="text-link" href="/blog/">บทความทั้งหมด</a>
-        <p class="eyebrow">{post.data.category} · {formattedDate}</p>
+        <a class="blog-back-link" href="/blog/">← บทความทั้งหมด</a>
+        <div class="blog-article-meta">
+          <span class="eyebrow eyebrow-yellow">{post.data.category}</span>
+          <span class="eyebrow">{formattedDate}</span>
+        </div>
         <h1>{post.data.title}</h1>
-        <p>{post.data.description}</p>
+        <p class="blog-article-lead">{post.data.description}</p>
       </div>
     </header>
 
     <div class="blog-article-shell">
-      <div class="blog-prose liquid-glass liquidGlass-wrapper">
-        <div class="liquidGlass-effect" aria-hidden="true"></div>
-        <div class="liquidGlass-tint" aria-hidden="true"></div>
-        <div class="liquidGlass-shine" aria-hidden="true"></div>
+      <div class="blog-prose">
         <Content />
       </div>
     </div>