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/config/index.d.ts

@@ -0,0 +1,12 @@
+import type { UserConfig as ViteUserConfig, UserConfigFn as ViteUserConfigFn } from 'vite';
+import type { FontProvider } from '../assets/fonts/types.js';
+import type { AstroInlineConfig, AstroUserConfig, Locales, SessionDriverName } from '../types/public/config.js';
+/**
+ * See the full Astro Configuration API Documentation
+ * https://astro.build/config
+ */
+export declare function defineConfig<const TLocales extends Locales = never, const TDriver extends SessionDriverName = never, const TFontProviders extends Array<FontProvider> = never>(config: AstroUserConfig<TLocales, TDriver, TFontProviders>): AstroUserConfig<TLocales, TDriver, TFontProviders>;
+/**
+ * Use Astro to generate a fully resolved Vite config
+ */
+export declare function getViteConfig(userViteConfig: ViteUserConfig, inlineAstroConfig?: AstroInlineConfig): ViteUserConfigFn;