fix: friendly Chinese error messages on login/register pages

Map backend English error details to user-facing Chinese text on all
3 frontends (uni-app, user-frontend, admin-frontend). Previously raw
English like 'Invalid credentials' was shown directly to users.

uni-app/src/pages/login/login.vue

@@ -229,10 +229,14 @@ const handleSubmit = async () => {
       }
   } catch (err) {
     console.error('登录失败', err)
-    error.value = (err.errMsg || err.message || '操作失败，请重试')
-    if (err.statusCode === 401) {
-      error.value = '手机号或密码错误'
+    const msg = err.errMsg || err.message || err.detail || ''
+    const map = {
+      'Invalid credentials': '手机号或密码错误',
+      'Phone already registered': '该手机号已被注册',
+      'Invalid refresh token': '登录已过期，请重新登录',
+      'phone required': '请输入手机号',
     }
+    error.value = map[msg] || msg || '操作失败，请重试'
   } finally {
     loading.value = false
   }