chore: untrack .tool-versions and gitignore version-manager pins

.tool-versions pins a single Python patch, which is a local-dev concern
inconsistent with a published library that supports a range (setup.cfg
python_requires + CI matrix 3.9-3.13). Matches existing handling of
.python-version and mise.toml.

Author: ancorcruz

.gitignore

@@ -72,5 +72,7 @@ Untitled.ipynb
 *.iml
 # End of https://www.toptal.com/developers/gitignore/api/python
 
+# asdf / mise version managers (local dev only; supported versions live in setup.cfg + CI)
+.tool-versions
 mise.toml
 .claude