♻️ 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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✅ Ready for Easypanel deployment (no root dir needed)

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

dealplustech-astro/node_modules/hast-util-to-html/lib/handle/root.js

@@ -1,22 +0,0 @@
-/**
- * @import {Parents, Root} from 'hast'
- * @import {State} from '../index.js'
- */
-
-/**
- * Serialize a root.
- *
- * @param {Root} node
- *   Node to handle.
- * @param {number | undefined} _1
- *   Index of `node` in `parent.
- * @param {Parents | undefined} _2
- *   Parent of `node`.
- * @param {State} state
- *   Info passed around about the current state.
- * @returns {string}
- *   Serialized node.
- */
-export function root(node, _1, _2, state) {
-  return state.all(node)
-}