Add ruff to copilot instructions

Author: mooneyc6

python-verso-routing/copilot-instructions.md

@@ -4,6 +4,7 @@
 
 Use [Nextmv python SDK][nextmv-py].
 Use Nextmv [documentation][nextmv-docs].
+Use [Ruff][ruff] for linting rules.
 
 ## Visualization
 
@@ -16,3 +17,4 @@ Add assets to the nextmv.Output.
 [nextmv-docs]: https://nextmv.io/docs
 [nextmv-py]: https://github.com/nextmv-io/nextmv-py
 [nextmv-docs-custom-viz]: https://nextmv.io/docs/using-nextmv/run/custom-visualization
+[ruff]: https://docs.astral.sh/ruff/