♻️ 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/rehype-stringify/index.d.ts

@@ -1,27 +0,0 @@
-import type {Root} from 'hast'
-import type {Plugin} from 'unified'
-import type {Options} from 'hast-util-to-html'
-
-export type {CharacterReferences, Options} from 'hast-util-to-html'
-
-/**
- * Plugin to add support for serializing as HTML.
- *
- * @this
- *   Unified processor.
- * @param
- *   Configuration (optional).
- * @returns
- *   Nothing.
- */
-declare const rehypeStringify: Plugin<
-  [(Options | null | undefined)?],
-  Root,
-  string
->
-export default rehypeStringify
-
-// Add custom settings supported when `rehype-stringify` is added.
-declare module 'unified' {
-  interface Settings extends Options {}
-}