fix: run.bat 错误分支加 pause；前端生产用 window.location.origin

- run.bat: :error 分支加 pause，避免创建 venv/装依赖失败时窗口一闪即关
- frontend app store: 开发用 127.0.0.1:8775，生产回落到 window.location.origin，跟后端同源直取

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/run.bat

@@ -18,6 +18,7 @@ goto :end
 
 :error
 echo [backend] 启动失败
+pause
 exit /b 1
 
 :end

frontend/src/stores/app.js

@@ -3,7 +3,8 @@ import { computed, ref } from 'vue'
 import { notify } from '@/utils/notify'
 
 export const useAppStore = defineStore('app', () => {
-  const apiBase = ref(localStorage.getItem('financeAiApiBase') || 'http://127.0.0.1:8775')
+  const defaultApiBase = import.meta.env.DEV ? 'http://127.0.0.1:8775' : window.location.origin
+  const apiBase = ref(localStorage.getItem('financeAiApiBase') || defaultApiBase)
   const token = ref(localStorage.getItem('financeAiToken') || '')
   const currentUser = ref(null)
   const healthy = ref(false)
@@ -17,7 +18,7 @@ export const useAppStore = defineStore('app', () => {
   }
 
   function setApiBase(value) {
-    apiBase.value = (value || '').trim() || 'http://127.0.0.1:8775'
+    apiBase.value = (value || '').trim() || defaultApiBase
     localStorage.setItem('financeAiApiBase', apiBase.value)
   }