feat: add banner to docs website welcome page

- Revert README to original banner
- Add waveform banner to docs site welcome page

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -1,4 +1,4 @@
-![BMad Method](banner-bmad-method2.png)
+![BMad Method](banner-bmad-method.png)
 
 [![Version](https://img.shields.io/npm/v/bmad-method?color=blue&label=version)](https://www.npmjs.com/package/bmad-method)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](LICENSE)

docs/index.md

@@ -2,6 +2,8 @@
 title: Welcome to the BMad Method
 ---
 
+![BMad Method](/img/banner-bmad-method2.png)
+
 The BMad Method (**B**reakthrough **M**ethod of **A**gile AI **D**riven Development) is an AI-driven development framework that helps you build software faster and smarter. It provides specialized AI agents, guided workflows, and intelligent planning that adapts to your project's complexity—whether you're fixing a bug or building an enterprise platform.
 
 If you're comfortable working with AI coding assistants like Claude, Cursor, or GitHub Copilot, you're ready to get started.