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/utils.d.ts

@@ -0,0 +1,5 @@
+import type { Element } from 'hast';
+import type MagicString from 'magic-string';
+export declare function replaceAttribute(s: MagicString, node: Element, key: string, newValue: string): MagicString | undefined;
+export declare function needsEscape(value: any): value is string;
+export declare function escapeTemplateLiteralCharacters(value: string): string;