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/runtime/server/astro-island-styles.js

@@ -0,0 +1,4 @@
+const ISLAND_STYLES = "astro-island,astro-slot,astro-static-slot{display:contents}";
+export {
+  ISLAND_STYLES
+};