refactor(web): 采用 Button/Card 原语替换多处手搓样式

apps/web/components/foreshadow/RegisterForm.tsx

@@ -5,6 +5,7 @@ import { Plus } from "lucide-react";
 
 import { Button } from "@/components/ui/Button";
 import { TextInput } from "@/components/ui/TextInput";
+import { cardClass } from "@/lib/ui/variants";
 import type { RegisterInput } from "@/lib/foreshadow/board";
 
 interface RegisterFormProps {
@@ -79,7 +80,7 @@ export function RegisterForm({
         e.preventDefault();
         void submit();
       }}
-      className="rounded border border-line bg-panel p-4"
+      className={cardClass("p-4")}
     >
       <div className="grid grid-cols-2 gap-3 sm:grid-cols-3">
         <FormSlot label="代号 *" id="f-code">