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/app/App.tsx

@@ -0,0 +1,40 @@
+import { useMemo, useState } from "react";
+import { Navigate, Route, Routes } from "react-router-dom";
+
+import { Layout } from "../components/Layout";
+import { AuditPage } from "../features/audit/AuditPage";
+import { LoginPage } from "../features/auth/LoginPage";
+import { DashboardPage } from "../features/dashboard/DashboardPage";
+import { DevicesPage } from "../features/devices/DevicesPage";
+import { GatewaysPage } from "../features/gateways/GatewaysPage";
+import { PoliciesPage } from "../features/policies/PoliciesPage";
+import { SettingsPage } from "../features/settings/SettingsPage";
+import { UsersPage } from "../features/users/UsersPage";
+
+export function App() {
+  const [token, setToken] = useState(() => localStorage.getItem("nexavpn_admin_token") ?? "");
+  const authenticated = useMemo(() => token.length > 0, [token]);
+
+  function handleAuthenticated(accessToken: string) {
+    localStorage.setItem("nexavpn_admin_token", accessToken);
+    setToken(accessToken);
+  }
+
+  return (
+    <Routes>
+      <Route
+        path="/login"
+        element={authenticated ? <Navigate to="/" replace /> : <LoginPage onAuthenticated={handleAuthenticated} />}
+      />
+      <Route element={authenticated ? <Layout /> : <Navigate to="/login" replace />}>
+        <Route path="/" element={<DashboardPage />} />
+        <Route path="/users" element={<UsersPage />} />
+        <Route path="/devices" element={<DevicesPage />} />
+        <Route path="/policies" element={<PoliciesPage />} />
+        <Route path="/gateways" element={<GatewaysPage />} />
+        <Route path="/audit" element={<AuditPage />} />
+        <Route path="/settings" element={<SettingsPage />} />
+      </Route>
+    </Routes>
+  );
+}