revert top BMC to shield badge, keep yellow button at bottom

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: AnjanJ

README.md

@@ -1,6 +1,6 @@
 # 🚀 AJ's Dotfiles
 
-<a href="https://www.buymeacoffee.com/anjanj" target="_blank"><img src="https://cdn.buymeacoffee.com/buttons/v2/default-yellow.png" alt="Buy Me A Coffee" width="200"></a>
+[![Buy Me A Coffee](https://img.shields.io/badge/Buy%20Me%20A%20Coffee-support-yellow?logo=buymeacoffee)](https://buymeacoffee.com/anjanj)
 
 > A complete macOS development environment — Ruby/Rails, Elixir/Phoenix, Node/React, Python, Go, Rust, Zig — with your choice of Tokyo Night, Aura Dark, or Catppuccin Mocha theme applied everywhere.