chore: stop tracking local Claude Code config

Remove .claude/settings.json from version control and add .claude/ to
.gitignore so local Claude Code config is no longer committed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: infrakaspper

.claude/settings.json

@@ -43,3 +43,6 @@ src/scripts/contributors/*.html
 
 # macOS metadata
 .DS_Store
+
+# Claude Code local config
+.claude/