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/Layout.tsx

@@ -0,0 +1,45 @@
+import { NavLink, Outlet } from "react-router-dom";
+
+const items = [
+  ["Dashboard", "/"],
+  ["Users", "/users"],
+  ["Devices", "/devices"],
+  ["Policies", "/policies"],
+  ["Gateways", "/gateways"],
+  ["Audit", "/audit"],
+  ["Settings", "/settings"]
+];
+
+export function Layout() {
+  return (
+    <div className="shell">
+      <aside className="sidebar">
+        <div>
+          <p className="eyebrow">NexaVPN</p>
+          <h1>Control Plane</h1>
+        </div>
+        <nav className="nav">
+          {items.map(([label, path]) => (
+            <NavLink
+              key={path}
+              to={path}
+              className={({ isActive }) => (isActive ? "nav-link active" : "nav-link")}
+            >
+              {label}
+            </NavLink>
+          ))}
+        </nav>
+      </aside>
+      <main className="content">
+        <header className="topbar">
+          <div>
+            <p className="eyebrow">Enterprise WireGuard</p>
+            <h2>Self-hosted VPN management</h2>
+          </div>
+          <div className="pill">Secure by design</div>
+        </header>
+        <Outlet />
+      </main>
+    </div>
+  );
+}