Initial commit: OpenVPN Manager v1.0

OpenVPN Web management console with multi-instance support, client cert
issuance, traffic/connection auditing, certificate expiry reminders,
auto backup/restore.

Stack:
- Backend: Go 1.21+ (Gin + JWT)
- Frontend: Vue 3 + Element Plus + ECharts + Vite
- Storage: JSON file (db.json) + filesystem (pki/, instances/, clients/, backups/)

Features:
- Multi-instance OpenVPN management (independent port/proto/subnet/PKI)
- One-click client certificate issuance with .ovpn (embedded certs)
- Certificate expiry reminders (30-day threshold)
- Connection log parsing (status-version 3)
- Auto backup/restore (tar.gz)
- Audit log for all write operations
- JWT auth (12h TTL)
- One-line install.sh for Ubuntu/Debian/RHEL/Fedora

frontend/vite.config.js

@@ -0,0 +1,22 @@
+import { defineConfig } from 'vite'
+import vue from '@vitejs/plugin-vue'
+import path from 'path'
+
+export default defineConfig({
+  plugins: [vue()],
+  resolve: {
+    alias: { '@': path.resolve(__dirname, 'src') }
+  },
+  server: {
+    port: 3000,
+    proxy: {
+      '/api': { target: 'http://127.0.0.1:8089', changeOrigin: true }
+    }
+  },
+  build: {
+    outDir: '../dist',
+    emptyOutDir: true,
+    sourcemap: false,
+    chunkSizeWarningLimit: 2000
+  }
+})