fix: 修复生产环境登录双/api路径问题

API_BASE为空时用||替代??，确保fallback到localhost:4000

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

apps/web/.env.production

@@ -1 +1 @@
-NEXT_PUBLIC_API_URL=/api
+NEXT_PUBLIC_API_URL=

apps/web/src/components/Sidebar.tsx

@@ -81,7 +81,7 @@ export default function Sidebar({
           }`}
         >
           <span>📋</span>
-          <span>线索池</span>
+          <span>询价发布助手</span>
         </button>
 
         {[

apps/web/src/lib/apiBase.ts

@@ -1 +1 @@
-export const API_BASE: string = process.env.NEXT_PUBLIC_API_URL ?? 'http://localhost:4000'
+export const API_BASE: string = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:4000'