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

desktop-client/src-tauri/tauri.conf.json

@@ -0,0 +1,30 @@
+{
+  "$schema": "https://schema.tauri.app/config/2",
+  "productName": "NexaVPN",
+  "version": "0.1.0",
+  "identifier": "com.nexavpn.desktop",
+  "build": {
+    "beforeDevCommand": "npm run dev",
+    "beforeBuildCommand": "npm run build",
+    "devUrl": "http://localhost:4173",
+    "frontendDist": "../dist"
+  },
+  "app": {
+    "windows": [
+      {
+        "title": "NexaVPN",
+        "width": 1120,
+        "height": 760,
+        "resizable": true
+      }
+    ],
+    "security": {
+      "csp": null
+    }
+  },
+  "bundle": {
+    "active": true,
+    "targets": "all",
+    "icon": []
+  }
+}