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/vfile/lib/minproc.browser.js

@@ -0,0 +1,8 @@
+// Somewhat based on:
+// <https://github.com/defunctzombie/node-process/blob/master/browser.js>.
+// But I don’t think one tiny line of code can be copyrighted. 😅
+export const minproc = {cwd}
+
+function cwd() {
+  return '/'
+}