docs: add CLAUDE.md noting empty scaffold state (#3)

Claude-Session: https://claude.ai/code/session_019zWjgFjCupJNvARzcFETtR

Co-authored-by: Claude <noreply@anthropic.com>

Author: seonghobae

CLAUDE.md

@@ -0,0 +1,15 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Current state
+
+This repository is an empty scaffold: it contains only a `.gitkeep` placeholder and a single initialization commit. There is no source code, build configuration, test suite, or documentation yet, so there are no build/lint/test commands to run and no architecture to describe.
+
+## When code lands here
+
+Replace this section with the real contents:
+
+- Commonly used commands (build, lint, test, and how to run a single test).
+- High-level architecture: the major components and how they interact.
+- Any project-specific conventions that are not obvious from individual files.