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/retext/index.js

@@ -0,0 +1,6 @@
+// Note: types exposed from `index.d.ts`.
+import {unified} from 'unified'
+import retextLatin from 'retext-latin'
+import retextStringify from 'retext-stringify'
+
+export const retext = unified().use(retextLatin).use(retextStringify).freeze()