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/infra/process-operating-system-provider.d.ts

@@ -0,0 +1,6 @@
+import type { OperatingSystemProvider } from '../definitions.js';
+export declare class ProcessOperatingSystemProvider implements OperatingSystemProvider {
+    #private;
+    readonly name: NodeJS.Platform;
+    readonly displayName: string;
+}