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-houdaun/src/main/java/com/test/bijihoudaun/service/RegistrationCodeService.java

@@ -0,0 +1,10 @@
+package com.test.bijihoudaun.service;
+
+import com.baomidou.mybatisplus.extension.service.IService;
+import com.test.bijihoudaun.entity.RegistrationCode;
+
+public interface RegistrationCodeService extends IService<RegistrationCode> {
+    String generateCode(String creator);
+    boolean validateCode(String code);
+    void deleteExpiredCodes();
+}

biji-houdaun/src/main/java/com/test/bijihoudaun/service/SystemSettingService.java

@@ -0,0 +1,9 @@
+package com.test.bijihoudaun.service;
+
+import com.baomidou.mybatisplus.extension.service.IService;
+import com.test.bijihoudaun.entity.SystemSetting;
+
+public interface SystemSettingService extends IService<SystemSetting> {
+    boolean isRegistrationEnabled();
+    void setRegistrationEnabled(boolean enabled);
+}

biji-houdaun/src/main/java/com/test/bijihoudaun/service/impl/RegistrationCodeServiceImpl.java

@@ -0,0 +1,55 @@
+package com.test.bijihoudaun.service.impl;
+
+import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
+import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
+import com.test.bijihoudaun.entity.RegistrationCode;
+import com.test.bijihoudaun.mapper.RegistrationCodeMapper;
+import com.test.bijihoudaun.service.RegistrationCodeService;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.LocalDateTime;
+import java.util.UUID;
+
+@Service
+public class RegistrationCodeServiceImpl extends ServiceImpl<RegistrationCodeMapper, RegistrationCode> implements RegistrationCodeService {
+
+    @Override
+    public String generateCode(String creator) {
+        RegistrationCode registrationCode = new RegistrationCode();
+        String code = UUID.randomUUID().toString().replaceAll("-", "").substring(0, 16);
+        registrationCode.setCode(code);
+        registrationCode.setCreatedBy(creator);
+        registrationCode.setExpiryTime(LocalDateTime.now().plusDays(1));
+        save(registrationCode);
+        return code;
+    }
+
+    @Override
+    @Transactional
+    public boolean validateCode(String code) {
+        QueryWrapper<RegistrationCode> queryWrapper = new QueryWrapper<>();
+        queryWrapper.eq("code", code);
+        RegistrationCode registrationCode = getOne(queryWrapper);
+
+        if (registrationCode == null) {
+            return false;
+        }
+
+        if (registrationCode.getExpiryTime().isBefore(LocalDateTime.now())) {
+            remove(queryWrapper); // 注册码过期，删除
+            return false;
+        }
+
+        // 验证成功后立即删除，确保一次性使用
+        remove(queryWrapper);
+        return true;
+    }
+
+    @Override
+    @Scheduled(cron = "0 0 1 * * ?") // 每天凌晨1点执行
+    public void deleteExpiredCodes() {
+        remove(new QueryWrapper<RegistrationCode>().lt("expiry_time", LocalDateTime.now()));
+    }
+}

biji-houdaun/src/main/java/com/test/bijihoudaun/service/impl/SystemSettingServiceImpl.java

@@ -0,0 +1,28 @@
+package com.test.bijihoudaun.service.impl;
+
+import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
+import com.test.bijihoudaun.entity.SystemSetting;
+import com.test.bijihoudaun.mapper.SystemSettingMapper;
+import com.test.bijihoudaun.service.SystemSettingService;
+import org.springframework.stereotype.Service;
+
+@Service
+public class SystemSettingServiceImpl extends ServiceImpl<SystemSettingMapper, SystemSetting> implements SystemSettingService {
+
+    private static final String REGISTRATION_ENABLED_KEY = "registration.enabled";
+
+    @Override
+    public boolean isRegistrationEnabled() {
+        SystemSetting setting = getById(REGISTRATION_ENABLED_KEY);
+        // 默认开启注册
+        return setting == null || Boolean.parseBoolean(setting.getSettingValue());
+    }
+
+    @Override
+    public void setRegistrationEnabled(boolean enabled) {
+        SystemSetting setting = new SystemSetting();
+        setting.setSettingKey(REGISTRATION_ENABLED_KEY);
+        setting.setSettingValue(String.valueOf(enabled));
+        saveOrUpdate(setting);
+    }
+}