Add TTRPG Player marketing landing site.

React/Vite landing with RU/EN i18n, live USD pricing, download links to updates.mailib.ru, and donate.stream checkout.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/components/ui/Button.tsx

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+import type { ReactNode } from "react";
+
+import styles from "./Button.module.css";
+
+type ButtonVariant = "primary" | "secondary" | "ghost" | "gold";
+
+type ButtonProps = {
+  children: ReactNode;
+  href?: string;
+  variant?: ButtonVariant;
+  className?: string;
+  onClick?: () => void;
+  type?: "button" | "submit";
+};
+
+function join(...parts: (string | undefined)[]): string {
+  return parts.filter(Boolean).join(" ");
+}
+
+export function Button({
+  children,
+  href,
+  variant = "primary",
+  className,
+  onClick,
+  type = "button",
+}: ButtonProps) {
+  const cls = join(styles.button, styles[variant], className);
+
+  if (href) {
+    return (
+      <a className={cls} href={href}>
+        {children}
+      </a>
+    );
+  }
+
+  return (
+    <button className={cls} type={type} onClick={onClick}>
+      {children}
+    </button>
+  );
+}