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/astro/dist/vite-plugin-html/transform/slots.d.ts

@@ -0,0 +1,8 @@
+import type { Root } from 'hast';
+import type MagicString from 'magic-string';
+import type { Plugin } from 'unified';
+declare const rehypeSlots: Plugin<[{
+    s: MagicString;
+}], Root>;
+export default rehypeSlots;
+export declare const SLOT_PREFIX = "___SLOTS___";