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/assets/endpoint/config.d.ts

@@ -0,0 +1,2 @@
+import type { AstroSettings, RoutesList } from '../../types/astro.js';
+export declare function injectImageEndpoint(settings: AstroSettings, manifest: RoutesList, mode: 'dev' | 'build', cwd?: string): void;