fix: stabilize external-db deployment and updates

frontend/src/pages/setup/index.vue

@@ -103,6 +103,10 @@
             <t-alert v-if="connectionResult" class="connection-result" theme="success" :close-btn="false">
               {{ connectionResult.message }}（{{ connectionResult.serverVersion }}）
             </t-alert>
+            <p class="setup-hint">
+              测试连接只读取 MySQL
+              版本，不创建或修改数据库对象；点击“完成安装”后，系统才会在指定的专用空库执行迁移并创建管理员。
+            </p>
 
             <div class="setup-actions">
               <t-button theme="primary" variant="outline" type="submit" :loading="testingConnection">
@@ -290,9 +294,7 @@ const adminRules = computed<Record<string, FormRule[]>>(() => ({
 
 const databaseFingerprint = computed(() => JSON.stringify(databaseForm));
 const connectionVerified = computed(
-  () =>
-    Boolean(connectionResult.value?.successful && connectionResult.value.schemaReady) &&
-    verifiedFingerprint.value === databaseFingerprint.value,
+  () => Boolean(connectionResult.value?.successful) && verifiedFingerprint.value === databaseFingerprint.value,
 );
 
 watch(databaseFingerprint, () => {
@@ -308,7 +310,7 @@ async function testConnection(context?: SubmitContext) {
     const result = await testSetupConnection({ ...databaseForm });
     connectionResult.value = result;
     verifiedFingerprint.value = databaseFingerprint.value;
-    MessagePlugin.success('数据库连接验证通过');
+    MessagePlugin.success(result.message || '数据库只读连接验证通过');
   } catch (error) {
     connectionResult.value = null;
     errorMessage.value = (error as Error).message || '数据库连接验证失败';
@@ -469,6 +471,13 @@ h1 {
   margin-bottom: 20px;
 }
 
+.setup-hint {
+  margin: -4px 0 20px;
+  color: var(--td-text-color-secondary);
+  font-size: 13px;
+  line-height: 20px;
+}
+
 .setup-content {
   min-width: 0;
 }

frontend/src/utils/request/Axios.ts

@@ -19,6 +19,31 @@ import type { AxiosRequestConfigRetry, RequestOptions, Result } from '@/types/ax
 import { AxiosCanceler } from './AxiosCancel';
 import type { CreateAxiosOptions } from './AxiosTransform';
 
+function localizeApiError(code: string | undefined, detail: string | undefined, status?: number): string {
+  const messages: Record<string, string> = {
+    DATABASE_CONNECTION_FAILED: '数据库连接失败，请检查地址、端口、库名和账号权限',
+    DATABASE_INITIALIZATION_FAILED: '数据库初始化失败，请确认使用专用空库并检查迁移权限',
+    DATABASE_ENGINE_NOT_SUPPORTED: '当前版本仅支持 MySQL 8.4',
+    MYSQL_VERSION_UNSUPPORTED: 'MySQL 版本不受支持，需要 MySQL 8.4.x',
+    DATABASE_COLLATION_PREPARATION_FAILED: '数据库字符集或排序规则准备失败',
+    DATABASE_MIGRATION_STATE_INVALID: '数据库迁移历史无效，请使用空库或先修复迁移状态',
+    DATABASE_SCHEMA_INSPECTION_FAILED: '数据库结构检查失败',
+    SETUP_CODE_INVALID: '安装码不正确',
+    SETUP_LOCKED: '安装向导已锁定',
+    SETUP_STATE_WRITE_FAILED: '安装状态文件写入失败，请检查应用目录权限',
+    ADMIN_PASSWORD_MISMATCH: '管理员密码确认不一致',
+  };
+  if (code && messages[code]) return messages[code];
+  if (detail && /[\u4E00-\u9FFF]/.test(detail)) return detail;
+  if (status === 401) return '登录会话已失效';
+  if (status === 403) return '当前账号没有执行此操作的权限';
+  if (status === 404) return '请求的资源不存在';
+  if (status === 409) return '数据已发生变化，请刷新后重试';
+  if (status === 422) return '提交的数据未通过校验';
+  if (status && status >= 500) return '服务器处理失败，请查看服务日志';
+  return '网络请求失败，请检查网络连接后重试';
+}
+
 /**
  * Axios 模块
  */
@@ -318,7 +343,7 @@ export class VAxios {
             const problem = e.response?.data as
               { code?: string; detail?: string; requestId?: string; fieldErrors?: Record<string, string> } | undefined;
             const requestId = problem?.requestId || e.response?.headers?.['x-request-id'];
-            const message = problem?.detail || (e.response?.status === 401 ? '登录会话已失效' : '网络请求失败');
+            const message = localizeApiError(problem?.code, problem?.detail, e.response?.status);
             const error = new Error(requestId ? `${message}（请求编号：${requestId}）` : message);
             Object.assign(error, {
               code: problem?.code,