ui: 登录页Logo单独显示，去掉背景框

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frontend/src/pages/auth/Login.tsx

@@ -90,9 +90,7 @@ export default function Login() {
         <div className="relative z-10 flex flex-col justify-between p-12 xl:p-16 text-white w-full">
           {/* Logo + 品牌名 */}
           <div className="flex items-center gap-3">
-            <div className="w-11 h-11 rounded-xl bg-white/15 backdrop-blur flex items-center justify-center overflow-hidden">
-              <Logo className="w-8 h-8 object-contain" />
-            </div>
+            <Logo className="w-11 h-11 object-contain" />
             <div>
               <div className="text-xl font-bold tracking-tight">嘉驰英才</div>
               <div className="text-xs text-white/60 mt-0.5">嘉驰英才（上海）信息科技有限公司</div>