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/vite-plugin-config-alias/index.d.ts

@@ -0,0 +1,6 @@
+import { type Plugin as VitePlugin } from 'vite';
+import type { AstroSettings } from '../types/astro.js';
+/** Returns a Vite plugin used to alias paths from tsconfig.json and jsconfig.json. */
+export default function configAliasVitePlugin({ settings, }: {
+    settings: AstroSettings;
+}): VitePlugin | null;