Add Claude badge and AI-first hint to README

Adds a GitHub callout at the top stating no IDE or local setup is
needed, plus an AI section with the Claude badge — consistent with
the other three sibling repos.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HBz49Je54TcVoPVmQyMgif

Author: claude

README.md

@@ -1,3 +1,9 @@
+> [!NOTE]
+> **No IDE or local setup required.** This repository is optimized for fully AI-assisted development using [Claude Code](https://claude.ai/code). No local toolchain, no IDE, nothing to install — everything works completely through Claude.
+
+**AI:**  
+[![Claude](https://img.shields.io/badge/Claude-D97757?logo=claude&logoColor=fff)](#)  
+
 **Build:**  
 ![Java 8+](https://img.shields.io/badge/Java-8%2B-informational)  
 ![Platform](https://img.shields.io/badge/Platform-Linux%20%7C%20macOS%20%7C%20Windows%20%7C%20Android-lightgrey)