Add .claude/ to .gitignore

Exclude Claude-specific settings from version control to keep local configurations private.

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

Co-Authored-By: Claude <[email protected]>

Author: nakamura-to

.claude/settings.local.json

@@ -4,4 +4,5 @@ out
 .gradle
 .kotlin
 /.sdkmanrc
-/codegen/src/main/kotlin
+/codegen/src/main/kotlin
+.claude/