test: 添加前端Vitest测试15项，覆盖安全修复验证

测试类:
- apiService.test.js (9项): P2-F2 admin token不回退、P2-C2 paymentNo移除、P2-C5 pageSize默认值
- loginRedirect.test.js (6项): P1-S5 Open Redirect校验

配置:
- 安装vitest/happy-dom/vue-test-utils
- vite.config.js添加test配置
- package.json添加test脚本

全部15项测试通过

frontend/package.json

@@ -6,18 +6,26 @@
   "scripts": {
     "dev": "vite",
     "build": "vite build",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "test": "vitest run",
+    "test:watch": "vitest"
   },
   "dependencies": {
-    "vue": "^3.4.21",
-    "vue-router": "^4.3.0",
-    "pinia": "^2.1.7",
+    "@ant-design/icons-vue": "^7.0.1",
+    "@element-plus/icons-vue": "^2.3.1",
+    "ant-design-vue": "^4.2.6",
+    "axios": "^1.13.6",
     "element-plus": "^2.6.1",
-    "@element-plus/icons-vue": "^2.3.1"
+    "pinia": "^2.1.7",
+    "vue": "^3.4.21",
+    "vue-router": "^4.3.0"
   },
   "devDependencies": {
     "@vitejs/plugin-vue": "^5.0.4",
+    "@vue/test-utils": "^2.4.6",
+    "happy-dom": "^20.8.4",
+    "sass": "^1.71.1",
     "vite": "^5.1.6",
-    "sass": "^1.71.1"
+    "vitest": "^4.1.0"
   }
 }