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-astro/utils.d.ts

@@ -0,0 +1,3 @@
+import type { PluginContainer } from 'vite';
+export declare const frontmatterRE: RegExp;
+export declare function loadId(pluginContainer: PluginContainer, id: string): Promise<string | undefined>;