Add CI status badge to README.

Link the smoke-test workflow badge for quick health visibility on repository and PR pages.

Made-with: Cursor

Author: ztothez

README.md

@@ -1,5 +1,7 @@
 # RPS League (Python Version)
 
+[![Smoke Test](https://github.com/ztothez/rps-league-app-python-fullstack/actions/workflows/smoke.yml/badge.svg)](https://github.com/ztothez/rps-league-app-python-fullstack/actions/workflows/smoke.yml)
+
 Python-first implementation of the Reaktor RPS assignment with a proper backend, persistent storage, robust sync, explicit data validation decisions, and a built-in web dashboard frontend.
 
 ## Stack