♻️ Restructure: Move Astro to repository root

BREAKING CHANGE: Astro project is now at repository root
- Removed dealplustech-astro subdirectory
- Moved all Astro files to root
- Updated PostCSS config to .cjs
- Removed old Next.js files

✅ 11 pages built successfully
✅ Cookie consent banner included
✅ Privacy/Terms links in footer
✅ Ready for Easypanel deployment (no root dir needed)

Migration path:
- Old structure: /dealplustech-astro/
- New structure: / (root)

public/robots.txt

@@ -1,25 +0,0 @@
-# Robots.txt for dealplustech.co.th
-# https://dealplustech.co.th
-
-User-agent: *
-Allow: /
-
-# Sitemap location
-Sitemap: https://dealplustech.co.th/sitemap.xml
-
-# Disallow admin and private paths
-Disallow: /api/
-Disallow: /_next/
-Disallow: /admin/
-
-# Allow all crawlers access to static assets
-User-agent: Googlebot
-Allow: /images/
-Allow: /fonts/
-
-User-agent: Bingbot
-Allow: /images/
-Allow: /fonts/
-
-# Crawl delay for respectful crawling
-Crawl-delay: 1