♻️ 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/micromark-extension-gfm-strikethrough/index.d.ts

@@ -1,24 +0,0 @@
-export {gfmStrikethroughHtml} from './lib/html.js'
-export {gfmStrikethrough} from './lib/syntax.js'
-
-/**
- * Configuration (optional).
- */
-export interface Options {
-  /**
-   * Whether to support strikethrough with a single tilde (default: `true`).
-   *
-   * Single tildes work on github.com, but are technically prohibited by the
-   * GFM spec.
-   */
-  singleTilde?: boolean | null | undefined
-}
-
-declare module 'micromark-util-types' {
-  interface TokenTypeMap {
-    strikethroughSequence: 'strikethroughSequence'
-    strikethroughSequenceTemporary: 'strikethroughSequenceTemporary'
-    strikethrough: 'strikethrough'
-    strikethroughText: 'strikethroughText'
-  }
-}