build: 适配管理端 flow 基路径

- 调整开发与分析环境的 base 和接口前缀为 /flow

- 更新 Vite 代理配置，兼容 /flow/api 与 /flow/userCenter

- 修复基路径下的 Logo 与启动加载图资源地址

easyflow-ui-admin/packages/@core/preferences/src/config.ts

@@ -1,5 +1,7 @@
 import type { Preferences } from './types';
 
+const assetBase = import.meta.env.BASE_URL || '/';
+
 const defaultPreferences: Preferences = {
   app: {
     accessMode: 'frontend',
@@ -65,10 +67,10 @@ const defaultPreferences: Preferences = {
   logo: {
     enable: true,
     fit: 'contain',
-    source: '/logo.svg',
-    sourceDark: '/logoDark.svg',
-    sourceMini: '/logoMini.svg',
-    sourceMiniDark: '/logoMiniDark.svg',
+    source: `${assetBase}logo.svg`,
+    sourceDark: `${assetBase}logoDark.svg`,
+    sourceMini: `${assetBase}logoMini.svg`,
+    sourceMiniDark: `${assetBase}logoMiniDark.svg`,
   },
   navigation: {
     accordion: true,