feat: add TypeScript definitions for LeetCodeCalendar component

Author: yashksaini-coder

leetcode-calendar.d.ts

@@ -0,0 +1,15 @@
+declare module 'leetcode-calendar' {
+  import { FC } from 'react';
+
+  interface LeetCodeCalendarProps {
+    username: string;
+    blockSize?: number;
+    blockMargin?: number;
+    fontSize?: number;
+    theme?: object;
+    style?: React.CSSProperties;
+  }
+
+  const LeetCodeCalendar: FC<LeetCodeCalendarProps>;
+  export default LeetCodeCalendar;
+}