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/astro/components/ResponsivePicture.astro

@@ -0,0 +1,12 @@
+---
+import { default as Picture, type Props as PictureProps } from './Picture.astro';
+
+type Props = PictureProps;
+
+const { class: className, ...props } = Astro.props;
+import './image.css';
+---
+
+{/* Applying class outside of the spread prevents it from applying unnecessary astro-* classes */}
+
+<Picture {...props} class={className} />