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

vite.config.ts

@@ -0,0 +1,12 @@
+import { defineConfig } from 'vite';
+
+export default defineConfig({
+  server: {
+    host: '0.0.0.0',
+    allowedHosts: true
+  },
+  preview: {
+    host: '0.0.0.0',
+    allowedHosts: true
+  }
+});