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-html/transform/index.d.ts

@@ -0,0 +1,4 @@
+export declare function transform(code: string, id: string): Promise<{
+    code: string;
+    map: import("magic-string").SourceMap;
+}>;