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/stringify-entities/lib/constant/dangerous.js

@@ -0,0 +1,16 @@
+/**
+ * List of legacy (that don’t need a trailing `;`) named references which could,
+ * depending on what follows them, turn into a different meaning
+ *
+ * @type {Array<string>}
+ */
+export const dangerous = [
+  'cent',
+  'copy',
+  'divide',
+  'gt',
+  'lt',
+  'not',
+  'para',
+  'times'
+]