feat(system): 实现注册码功能并优化用户注册流程

- 新增注册码生成和验证功能- 实现系统设置管理，包括注册功能开关
- 更新前端界面，增加系统管理和注册码相关功能
- 修改数据库结构，添加系统设置和注册码表

biji-qianduan/src/api/CommonApi.js

@@ -66,6 +66,7 @@ export const register = (data) => {
     const formData = new FormData()
     formData.append('username', data.username)
     formData.append('password', data.password)
+    formData.append('registrationCode', data.registrationCode)
     return axiosApi.post('/api/user/register', formData, {
         headers: {
             'Content-Type': 'multipart/form-data'
@@ -132,3 +133,20 @@ export const cleanTrash = () => axiosApi.delete('/api/trash/clean');
 
 // 验证Token
 export const validateToken = () => axiosApi.post('/api/user/validate-token');
+
+// System APIs
+export const getRegistrationStatus = () => {
+    return axiosApi.get('/system/registration/status');
+};
+
+export const toggleRegistration = (enabled) => {
+    return axiosApi.post('/system/registration/toggle', enabled, {
+        headers: {
+            'Content-Type': 'application/json'
+        }
+    });
+};
+
+export const generateRegistrationCode = () => {
+    return axiosApi.post('/system/registration/generate-code');
+};