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/rehype/index.d.ts

@@ -0,0 +1,11 @@
+/// <reference types="rehype-parse" />
+/// <reference types="rehype-stringify" />
+
+import type {Root} from 'hast'
+import type {Processor} from 'unified'
+
+/**
+ * Create a new unified processor that already uses `rehype-parse` and
+ * `rehype-stringify`.
+ */
+export const rehype: Processor<Root, undefined, undefined, Root, string>