Update insulation brand pages (Armaflex, Aeroflex, Maxflex)

- Added 3 new brand pages: armflex.astro, aeroflex.astro, maxflex.astro
- Updated hero images with product photos from 3t-insulation.com
- Enhanced content with product specifications and benefits
- Added standard certifications (FM Approved, UL 94, GREENGUARD)
- Added product gallery sections
- Shortened menu names to brand only (Armaflex, Aeroflex, Maxflex)
- Removed old ฉนวนหุ้มท่อ.astro page
- Updated Header and BaseLayout navigation
- Downloaded product images for all 3 brands

src/pages/ท่อ-hdpe.astro

@@ -60,7 +60,7 @@ import BaseLayout from '@/layouts/BaseLayout.astro';
 
     <!-- Product Details -->
     <section class="py-16 bg-white">
-      <div class="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8">
+      <div class="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 relative z-10">
         <div class="max-w-4xl mx-auto">
           <h2 class="text-2xl font-bold text-primary-700 mb-8">รายละเอียดสินค้า</h2>
           <div class="prose prose-lg max-w-none">