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/env/vite-plugin-env.d.ts

@@ -0,0 +1,10 @@
+import type { Plugin } from 'vite';
+import type { AstroSettings } from '../types/astro.js';
+import type { EnvLoader } from './env-loader.js';
+interface AstroEnvPluginParams {
+    settings: AstroSettings;
+    sync: boolean;
+    envLoader: EnvLoader;
+}
+export declare function astroEnv({ settings, sync, envLoader }: AstroEnvPluginParams): Plugin;
+export {};