style(frontend): enhance button styling in AssistantPage

Update button styles in AssistantPage to include minimum width and padding for better layout consistency across different screen sizes.

frontend/src/components/pages/AssistantPage.tsx

@@ -927,13 +927,16 @@ export function AssistantPage(props: AssistantPageProps) {
           <div className="flex w-full shrink-0 flex-col gap-2 sm:w-auto sm:flex-row">
             <Button
               variant="outline"
-              className="w-full gap-2 border-hairline-strong text-foreground hover:bg-surface-strong sm:w-auto"
+              className="w-full min-w-[7.5rem] gap-2 border-hairline-strong px-4 text-foreground hover:bg-surface-strong sm:w-auto"
               onClick={() => router.push("/assistants/templates")}
             >
               <LayoutTemplate size={16} />
               模版库
             </Button>
-            <Button className="w-full shrink-0 gap-2 sm:w-auto" onClick={startCreate}>
+            <Button
+              className="w-full min-w-[7.5rem] shrink-0 gap-2 px-4 sm:w-auto"
+              onClick={startCreate}
+            >
               <Plus size={16} />
               创建助手
             </Button>