fix: fix iframe agent selector width

frontend-web/src/pages/IframeChatPage.tsx

@@ -711,7 +711,7 @@ export default function IframeChatPage() {
                       选择智能体进入问答
                     </div>
                     <div className="mt-4 flex flex-wrap items-center justify-center gap-2">
-                      <label className="relative inline-flex h-9 min-w-40 items-center rounded-full border border-[#eee3d5] bg-[#fffaf5] px-3 text-[#7e6a57] shadow-sm transition-colors hover:bg-white">
+                      <label className="relative inline-flex h-9 w-40 shrink-0 items-center rounded-full border border-[#eee3d5] bg-[#fffaf5] px-3 text-[#7e6a57] shadow-sm transition-colors hover:bg-white">
                         <BotIcon className="mr-2 size-3.5 shrink-0" />
                         <select
                           aria-label="选择智能体并进入问答"