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/@astrojs/markdown-remark/dist/rehype-prism.js

@@ -0,0 +1,19 @@
+import { runHighlighterWithAstro } from "@astrojs/prism/dist/highlighter";
+import { highlightCodeBlocks } from "./highlight.js";
+const rehypePrism = (excludeLangs) => {
+  return async (tree) => {
+    await highlightCodeBlocks(
+      tree,
+      (code, language) => {
+        let { html, classLanguage } = runHighlighterWithAstro(language, code);
+        return Promise.resolve(
+          `<pre class="${classLanguage}" data-language="${language}"><code is:raw class="${classLanguage}">${html}</code></pre>`
+        );
+      },
+      excludeLangs
+    );
+  };
+};
+export {
+  rehypePrism
+};