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/cli/docs/definitions.d.ts

@@ -0,0 +1,4 @@
+import type { CloudIde } from './domain/cloud-ide.js';
+export interface CloudIdeProvider {
+    readonly name: CloudIde | null;
+}