fix: link NPM badges to the package page on npmjs.com (#196)

The NPM Version and NPM Downloads badges were plain images with no
hyperlink. Wrap them in anchors pointing to the @reactuses/core
package page so users can click through to npm.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Faithfinder

README.md

@@ -8,8 +8,8 @@
 </p>
 
 <p align="center">
-  <img alt="NPM Version" src="https://img.shields.io/npm/v/@reactuses/core?style=for-the-badge&labelColor=24292e">
-  <img alt="NPM Downloads" src="https://img.shields.io/npm/dm/@reactuses/core?color=50a36f&label=&style=for-the-badge&labelColor=24292e">
+  <a href="https://www.npmjs.com/package/@reactuses/core"><img alt="NPM Version" src="https://img.shields.io/npm/v/@reactuses/core?style=for-the-badge&labelColor=24292e"></a>
+  <a href="https://www.npmjs.com/package/@reactuses/core"><img alt="NPM Downloads" src="https://img.shields.io/npm/dm/@reactuses/core?color=50a36f&label=&style=for-the-badge&labelColor=24292e"></a>
   <img alt="UnLicense" src="https://img.shields.io/npm/l/@reactuses/core?style=for-the-badge&labelColor=24292e">
   <img alt="Tree Shaking Friendly" src="https://img.shields.io/badge/Tree%20Shaking-Friendly-brightgreen?style=for-the-badge&labelColor=24292e">
   <img alt="TypeScript Support" src="https://img.shields.io/badge/TypeScript-Support-blue?style=for-the-badge&labelColor=24292e">