docs: make official source badge link to repository

Convert the official source badge into a clickable link to the canonical GitHub repository so users don't land on the raw badge image.

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

Author: sahmk-sa

README.md

@@ -1,6 +1,6 @@
 # SAHMK Python SDK
 
-![Official Source](https://img.shields.io/badge/Source-Official%20Only-0A66C2?style=for-the-badge)
+[![Official Source](https://img.shields.io/badge/Source-Official%20Only-0A66C2?style=for-the-badge)](https://github.com/sahmk-sa/sahmk-python)
 
 > **Official distribution:** GitHub (sahmk-sa) and PyPI only. Do not download binaries from third-party forks.