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/mdast-util-to-markdown/lib/handle/html.js

@@ -0,0 +1,20 @@
+/**
+ * @import {Html} from 'mdast'
+ */
+
+html.peek = htmlPeek
+
+/**
+ * @param {Html} node
+ * @returns {string}
+ */
+export function html(node) {
+  return node.value || ''
+}
+
+/**
+ * @returns {string}
+ */
+function htmlPeek() {
+  return '<'
+}