python: restore formatting for ty-based modules

[ryantm]

Why

Switching Python modules from pyright-extended to ty removed formatting support in the default Python module experience.

What changed

• Added a Ruff formatter to the ty module via replit.dev.formatters.ruff.
• Added a run-ruff-format wrapper that understands our formatter option contract (--stdin, --apply, and --file).
• Updated python modules to import ../ty so ty language-server + formatter behavior is shared in one place.
• Made ty module metadata and PATH defaults use lib.mkDefault so it can be safely imported into other modules.

Test plan

• direnv exec /home/developer/replit/nixmodules nix build --no-link --print-out-paths '.#activeModules.\"python-3.11\"' '.#activeModules.ty'
• Confirmed the build succeeds and emits both module artifacts.
• Confirmed the run-ruff-format derivation check phase passes for both stdout formatting and --apply mode.

Revertibility

Safe to revert. This change only affects module wiring and formatter configuration and does not modify stateful data or irreversible behavior.

Rollout

• This is fully backward and forward compatible

~ written by Zerg 👾