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/@astrojs/markdown-remark/dist/rehype-prism.d.ts

@@ -0,0 +1,3 @@
+import type { Root } from 'hast';
+import type { Plugin } from 'unified';
+export declare const rehypePrism: Plugin<[string[]?], Root>;