Update build status badge to shields.io format

- Changed from GitHub's native badge to shields.io format
- Uses img.shields.io for consistent styling with other badges
- Explicitly shows "build" label and tracks main branch status

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

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

Author: challgren

README.md

@@ -1,6 +1,6 @@
 # Aircraft Patterns - Pattern Detection for ADS-B/TAR1090
 
-[![Build Status](https://github.com/challgren/aircraft-patterns/actions/workflows/deploy.yml/badge.svg?branch=main)](https://github.com/challgren/aircraft-patterns/actions/workflows/deploy.yml)
+[![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/challgren/aircraft-patterns/deploy.yml?branch=main&label=build)](https://github.com/challgren/aircraft-patterns/actions/workflows/deploy.yml)
 [![Security Scan](https://github.com/challgren/aircraft-patterns/actions/workflows/security.yml/badge.svg)](https://github.com/challgren/aircraft-patterns/actions/workflows/security.yml)
 [![Python Lint](https://github.com/challgren/aircraft-patterns/actions/workflows/python-lint.yml/badge.svg)](https://github.com/challgren/aircraft-patterns/actions/workflows/python-lint.yml)
 [![Docker Image](https://ghcr-badge.egpl.dev/challgren/aircraft-patterns/size?tag=latest&label=image%20size)](https://github.com/challgren/aircraft-patterns/pkgs/container/aircraft-patterns)