refactor: Move Astro to root, use PORT env (default 80), allow all hosts

- Move Astro files from dealplustech-astro/ to project root
- Update Dockerfile: PORT environment variable (default 80)
- Add vite.config.ts with allowedHosts: true
- Matches nixpacks behavior for Easypanel deployment
- No hardcoded ports or domains

node_modules/mdast-util-gfm-strikethrough/index.js

@@ -0,0 +1,5 @@
+// Note: extra types in `index.d.ts`.
+export {
+  gfmStrikethroughFromMarkdown,
+  gfmStrikethroughToMarkdown
+} from './lib/index.js'