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/retext-stringify/lib/index.d.ts

@@ -0,0 +1,8 @@
+/**
+ * Add support for serializing natural language.
+ *
+ * @returns {undefined}
+ *   Nothing.
+ */
+export default function retextStringify(): undefined;
+export type Root = import('nlcst').Root;