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.js

@@ -0,0 +1,17 @@
+import { defineConfig, loadEnv } from 'vite';
+import react from '@vitejs/plugin-react';
+export default defineConfig(function (_a) {
+    var mode = _a.mode;
+    var env = loadEnv(mode, process.cwd(), '');
+    var apiTarget = env.VITE_DEV_API_TARGET || 'http://localhost:5090';
+    return {
+        plugins: [react()],
+        server: {
+            port: 5173,
+            proxy: {
+                '/api': { target: apiTarget, changeOrigin: true },
+                '/openapi': { target: apiTarget, changeOrigin: true },
+            },
+        },
+    };
+});