♻️ 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
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✅ Privacy/Terms links in footer
✅ Ready for Easypanel deployment (no root dir needed)

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

dealplustech-astro/node_modules/@astrojs/markdown-remark/dist/rehype-prism.js

@@ -1,19 +0,0 @@
-import { runHighlighterWithAstro } from "@astrojs/prism/dist/highlighter";
-import { highlightCodeBlocks } from "./highlight.js";
-const rehypePrism = (excludeLangs) => {
-  return async (tree) => {
-    await highlightCodeBlocks(
-      tree,
-      (code, language) => {
-        let { html, classLanguage } = runHighlighterWithAstro(language, code);
-        return Promise.resolve(
-          `<pre class="${classLanguage}" data-language="${language}"><code is:raw class="${classLanguage}">${html}</code></pre>`
-        );
-      },
-      excludeLangs
-    );
-  };
-};
-export {
-  rehypePrism
-};