fix: 安装页面API路径重复问题

api.ts的BASE_URL=/api/v1，安装页面调用api.get('/api/install/status')
导致实际请求路径为/api/v1/api/install/status（404）。
改为fetch直接请求避免baseURL前缀叠加。

frontend/src/pages/install/index.vue

@@ -4,8 +4,6 @@ import { computed, onMounted, ref } from 'vue'
 import { useRouter } from 'vue-router'
 import { toast } from 'vue-sonner'
 
-import api from '@/services/api'
-
 const router = useRouter()
 
 const loading = ref(false)
@@ -41,9 +39,10 @@ const dbTypes = [
 async function checkInstallStatus() {
   checkingStatus.value = true
   try {
-    const data = await api.get<any>('/api/install/status')
-    installStatus.value = data
-    if (data?.installed) {
+    const res = await fetch('/api/install/status')
+    const data = await res.json()
+    installStatus.value = data?.data
+    if (data?.data?.installed) {
       router.push('/auth/login')
     }
   }
@@ -68,8 +67,16 @@ async function testDatabase() {
       payload.username = form.value.db_username
       payload.password = form.value.db_password
     }
-    const data = await api.post<any>('/api/install/test-db', payload)
-    toast.success(data?.message || '数据库连接成功')
+    const res = await fetch('/api/install/test-db', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(payload),
+    })
+    const result = await res.json()
+    if (!res.ok || result.code !== 200) {
+      throw new Error(result.message || '数据库连接失败')
+    }
+    toast.success(result.data?.message || '数据库连接成功')
   }
   catch (error: any) {
     toast.error(error.message || '数据库连接失败')
@@ -130,8 +137,16 @@ async function handleInstall() {
       payload.redis_db = form.value.redis_db
     }
 
-    const data = await api.post<any>('/api/install/setup', payload)
-    toast.success(data?.message || '安装成功')
+    const res = await fetch('/api/install/setup', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(payload),
+    })
+    const result = await res.json()
+    if (!res.ok || result.code !== 200) {
+      throw new Error(result.message || '安装失败')
+    }
+    toast.success(result.data?.message || '安装成功')
     step.value = 4
   }
   catch (error: any) {