docs: add CI badge to README

Author: CynaCons

README.md

@@ -1,5 +1,7 @@
 # FinOracle - Your Personal Finance Oracle
 
+[![CI](https://github.com/CynaCons/FinOracle/actions/workflows/ci.yml/badge.svg)](https://github.com/CynaCons/FinOracle/actions/workflows/ci.yml)
+
 **A privacy-first, browser-based finance analytics platform for intelligent transaction categorization, insights, and planning.**
 
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