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/components/HomePage.vue

@@ -88,6 +88,7 @@
               <div v-if="userStore.isLoggedIn" class="user-actions">
                 <span class="welcome-text">欢迎, {{ userStore.userInfo?.username }}</span>
                 <el-button type="danger" @click="handleLogout">退出</el-button>
+                <el-button type="warning" @click="showSystemSettingsDialog = true">系统管理</el-button>
                 <el-button type="primary" @click="showCreateNoteDialog = true">新建笔记</el-button>
                 <el-upload
                   class="upload-btn"
@@ -203,6 +204,28 @@
             <el-button type="primary" @click="handleMoveNote">确定</el-button>
           </template>
         </el-dialog>
+
+        <!-- 系统管理对话框 -->
+        <el-dialog v-model="showSystemSettingsDialog" title="系统管理" width="500px">
+          <el-form label-width="120px">
+            <el-form-item label="开放注册">
+              <el-switch v-model="isRegistrationEnabled" @change="handleToggleRegistration"></el-switch>
+            </el-form-item>
+            <el-form-item label="生成注册码">
+              <el-button type="primary" @click="handleGenerateCode">生成</el-button>
+            </el-form-item>
+            <el-form-item v-if="generatedCode" label="新注册码">
+              <el-input v-model="generatedCode" readonly>
+                <template #append>
+                  <el-button @click="copyToClipboard(generatedCode)">复制</el-button>
+                </template>
+              </el-input>
+            </el-form-item>
+          </el-form>
+          <template #footer>
+            <el-button @click="showSystemSettingsDialog = false">关闭</el-button>
+          </template>
+        </el-dialog>
       </el-main>
     </el-container>
   </el-container>
@@ -225,7 +248,10 @@ import {
   updateMarkdownTitle,
   deleteGrouping as apiDeleteGrouping,
   getRecentFiles,
-  validateToken
+  validateToken,
+  getRegistrationStatus,
+  toggleRegistration,
+  generateRegistrationCode
 } from '@/api/CommonApi.js'
 import { Plus, Fold, Expand, Folder, Document, Search, Edit, Delete, ArrowDown, Clock } from "@element-plus/icons-vue";
 import { useUserStore } from '../stores/user';
@@ -253,6 +279,9 @@ const fileToImport = ref(null);
 const showMoveNoteDialog = ref(false);
 const moveToGroupId = ref(null);
 const currentGroupName = ref('');
+const showSystemSettingsDialog = ref(false);
+const isRegistrationEnabled = ref(true);
+const generatedCode = ref('');
 
 const groupFormRef = ref(null);
 const newGroupForm = ref({ name: '', parentId: null });
@@ -921,6 +950,44 @@ watch(activeMenu, (newVal) => {
     resetToHomeView();
   }
 });
+
+const handleToggleRegistration = async (value) => {
+  try {
+    await toggleRegistration(value);
+    ElMessage.success(`注册功能已${value ? '开启' : '关闭'}`);
+  } catch (error) {
+    ElMessage.error('操作失败');
+    isRegistrationEnabled.value = !value; // revert
+  }
+};
+
+const handleGenerateCode = async () => {
+  try {
+    const response = await generateRegistrationCode();
+    generatedCode.value = response.data;
+    ElMessage.success('注册码生成成功');
+  } catch (error) {
+    ElMessage.error('生成注册码失败');
+  }
+};
+
+const copyToClipboard = (text) => {
+  navigator.clipboard.writeText(text).then(() => {
+    ElMessage.success('已复制到剪贴板');
+  }, () => {
+    ElMessage.error('复制失败');
+  });
+};
+
+onMounted(async () => {
+  // ... existing onMounted logic
+  try {
+    const response = await getRegistrationStatus();
+    isRegistrationEnabled.value = response.data;
+  } catch (error) {
+    console.error("Failed to fetch registration status:", error);
+  }
+});
 </script>
 
 <style>