feat: replace all emojis with professional lucide-style SVG icon library

Build a curated 50-icon lucide library (Icon.astro + icon-paths.ts) and
replace every emoji across the site (~50 occurrences in 9 files):
- index.astro: 3 problem cards (message, trendingDown, globe)
- about.astro: 4 value cards (target, users, clock, shield)
- portfolio.astro: 7 industry filter buttons (factory, package, scale,
  graduationCap, trendingUp, pen, shoppingCart, layers)
- services/[slug].astro: ~25 feature/target/service icons
- services/index.astro: 6 decision-row tags + phone icon in CTA
- faq.astro: 5 category icons, 3 channel cards
- contact.astro: 3 channel picker, 5 info column, form options data-driven,
  checkCircle success
- Footer.astro: 3 contact icons (phone, mail, mapPin)
- Hero.astro: award icon in trust strip

Add icon wrapper styles to global.css (.problem-icon, .value-icon,
.channel-pick-icon, .info-icon, .channel-icon, .category-icon,
.feature-icon, .target-icon, .success-icon, .contact-icon, .btn-icon,
.filter-icon) — yellow square/circle backgrounds, dark text, consistent
sizing.

Build: 18 pages, 0 errors

src/pages/blog/[slug].astro

@@ -54,7 +54,7 @@ const formattedDate = post.data.date.toLocaleDateString('th-TH', {
 
   <section class="section article-section">
     <div class="container">
-      <div class="article-grid">
+      <div class="article-grid reveal">
         <article class="article-content">
           <div class="article-body">
             <Content />