docs: add dshfind badge to README (#15)

dsh-context is listed on dshfind (a DeepSeek Harness plugin directory)
and currently carries the "Featured" mark there. The badge links back to
the listing page.


Claude-Session: https://claude.ai/code/session_01Qj6wERPu4n2to3KmBXcVEz

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

README.md

@@ -4,6 +4,7 @@
 
 [![npm version](https://img.shields.io/npm/v/dsh-context)](https://www.npmjs.com/package/dsh-context)
 [![GitHub stars](https://img.shields.io/github/stars/bowenliang123/dsh-context?style=social)](https://github.com/bowenliang123/dsh-context)
+[![dshfind](https://dshfind.com/api/badge/bowenliang123/dsh-context)](https://dshfind.com/en/plugins/bowenliang123/dsh-context?ref=badge)
 
 **The best [DeepSeek Harness plugin](https://www.deepseek.com/harness/) for Agent's context insights and management.**