chore: import upstream snapshot with attribution

docs/components/button.tsx

@@ -0,0 +1,46 @@
+import Link from "next/link";
+import type { ButtonHTMLAttributes, ComponentProps } from "react";
+
+const SIZES = {
+  sm: "h-8 px-4 text-[0.8125rem]",
+  md: "h-10 px-6 text-sm",
+  lg: "h-11 gap-2 px-8 text-[0.9375rem]",
+};
+
+const VARIANTS = {
+  default: "border-border bg-bg text-fg hover:border-fg",
+  primary:
+    "border-accent bg-accent text-accent-fg hover:bg-transparent hover:text-accent",
+};
+
+type ButtonVariant = keyof typeof VARIANTS;
+type ButtonSize = keyof typeof SIZES;
+
+type ButtonStyleProps = {
+  variant?: ButtonVariant;
+  size?: ButtonSize;
+  className?: string;
+};
+
+function classes({ variant = "default", size = "md", className = "" }: ButtonStyleProps): string {
+  return [
+    "inline-flex items-center justify-center rounded-md border font-medium no-underline transition",
+    VARIANTS[variant],
+    SIZES[size],
+    className,
+  ]
+    .filter(Boolean)
+    .join(" ");
+}
+
+type ButtonProps = ButtonHTMLAttributes<HTMLButtonElement> & ButtonStyleProps;
+
+export function Button({ variant, size, className, ...rest }: ButtonProps) {
+  return <button className={classes({ variant, size, className })} {...rest} />;
+}
+
+type ButtonLinkProps = ComponentProps<typeof Link> & ButtonStyleProps;
+
+export function ButtonLink({ variant, size, className, ...rest }: ButtonLinkProps) {
+  return <Link className={classes({ variant, size, className })} {...rest} />;
+}