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/dist/runtime/client/visible.d.ts

@@ -0,0 +1,8 @@
+import type { ClientDirective } from '../../types/public/integrations.js';
+/**
+ * Hydrate this component when one of it's children becomes visible
+ * We target the children because `astro-island` is set to `display: contents`
+ * which doesn't work with IntersectionObserver
+ */
+declare const visibleDirective: ClientDirective;
+export default visibleDirective;