feat: add Vite configuration for Tiku.PlatformAdmin.Web and update documentation

- Introduced Vite configuration files (vite.config.js, vite.config.ts, vite.config.d.ts) for the React frontend.
- Configured server proxy settings for API endpoints.
- Added Vitest configuration files (vitest.config.js, vitest.config.ts, vitest.config.d.ts) for testing.
- Updated architecture overview to reflect the separation of the platform admin frontend into its own React project.
- Modified quickstart documentation to guide users on starting the platform admin frontend.

Tiku.PlatformAdmin.Web/vite.config.ts

@@ -0,0 +1,29 @@
+import { defineConfig, loadEnv } from 'vite';
+import react from '@vitejs/plugin-react';
+
+export default defineConfig(({ mode }) => {
+  const env = loadEnv(mode, process.cwd(), '');
+  const apiTarget = env.VITE_DEV_API_TARGET || 'http://localhost:5090';
+
+  return {
+    plugins: [react()],
+    build: {
+      rollupOptions: {
+        output: {
+          manualChunks(id) {
+            if (id.includes('node_modules/react') || id.includes('node_modules/scheduler')) return 'react';
+            if (id.includes('node_modules/antd') || id.includes('node_modules/@ant-design') || id.includes('node_modules/rc-')) return 'antd';
+            if (id.includes('node_modules')) return 'vendor';
+          },
+        },
+      },
+    },
+    server: {
+      port: 5173,
+      proxy: {
+        '/api': { target: apiTarget, changeOrigin: true },
+        '/openapi': { target: apiTarget, changeOrigin: true },
+      },
+    },
+  };
+});