refactor(biji): 更新 API基础路径和相关调用

- 将 VITE_API_BASE_URL 从 https://biji-houdaun.311169.xyz 修改为 /api- 更新前端 API 调用路径，统一添加 /api前缀
- 修改后端 SecurityConfig 和 SystemController，以适应新的 API 路径

biji-qianduan/src/api/CommonApi.js

@@ -136,11 +136,11 @@ export const validateToken = () => axiosApi.post('/api/user/validate-token');
 
 // System APIs
 export const getRegistrationStatus = () => {
-    return axiosApi.get('/system/registration/status');
+    return axiosApi.get('/api/system/registration/status');
 };
 
 export const toggleRegistration = (enabled) => {
-    return axiosApi.post('/system/registration/toggle', enabled, {
+    return axiosApi.post('/api/system/registration/toggle', enabled, {
         headers: {
             'Content-Type': 'application/json'
         }
@@ -148,7 +148,7 @@ export const toggleRegistration = (enabled) => {
 };
 
 export const generateRegistrationCode = () => {
-    return axiosApi.post('/system/registration/generate-code');
+    return axiosApi.post('/api/system/registration/generate-code');
 };
 
 // 更新密码