Fix markdown linting: add blank line before Features heading

Resolve MD022 linting error by adding required blank line between
screenshot image and ## 🎯 Features heading.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: challgren

README.md

@@ -13,6 +13,7 @@
 Real-time aircraft pattern detection system that monitors TAR1090 feeds to identify and log circular holding patterns, training flights, and grid survey patterns.
 
 ![Aircraft Pattern Detector Screenshot](docs/images/screenshot.png)
+
 ## 🎯 Features
 
 ### Pattern Detection