chore: initial project scaffold with admin web, backend, desktop client, and deployment setup

Add monorepo structure for NexaVPN WireGuard control plane including:
- .gitignore for node_modules, build artifacts, and environment files
- README with project overview, monorepo layout, and quick start guide
- Admin web UI with React, Vite, TypeScript, and nginx reverse proxy
- API client with type definitions for users, devices, policies, gateways, and audit logs
- Admin pages for dashboard, users, devices, policies, g

admin-web/src/components/Card.tsx

@@ -0,0 +1,5 @@
+import { PropsWithChildren } from "react";
+
+export function Card({ children }: PropsWithChildren) {
+  return <div className="card">{children}</div>;
+}