chore: gitignore .tool-versions (asdf)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.gitignore

@@ -80,3 +80,6 @@ htmlcov/
 
 # Crash recovery artifacts
 ai-cli-crash-capture/
+
+# asdf version manager
+.tool-versions