feat(admin): set /admin base path for reverse proxy deployment

Configure Vite base, Vue Router history, axios baseURL and container
Nginx to serve the admin panel under /admin/ path prefix.

🤖 Generated with [Qoder][https://qoder.com]

apps/admin/vite.config.ts

@@ -3,6 +3,7 @@ import vue from '@vitejs/plugin-vue';
 import { resolve } from 'path';
 
 export default defineConfig({
+  base: '/admin/',
   plugins: [vue()],
   resolve: {
     // 避免 src 内遗留的 .js 抢先于 .ts/.vue 被解析（曾导致 i18n 文案缺失）
@@ -15,6 +16,12 @@ export default defineConfig({
   publicDir: resolve(__dirname, '../../packages/shared/public'),
   server: {
     port: 5174,
-    proxy: { '/api': { target: 'http://localhost:3000', changeOrigin: true } },
+    proxy: {
+      '/admin/api': {
+        target: 'http://localhost:3000',
+        changeOrigin: true,
+        rewrite: (path) => path.replace(/^\/admin\/api/, '/api'),
+      },
+    },
   },
 });