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/env/vite-plugin-import-meta-env.d.ts

@@ -0,0 +1,7 @@
+import type * as vite from 'vite';
+import type { EnvLoader } from './env-loader.js';
+interface EnvPluginOptions {
+    envLoader: EnvLoader;
+}
+export declare function importMetaEnv({ envLoader }: EnvPluginOptions): vite.Plugin;
+export {};