Add pre-commit config, GitHub Actions (GEN-279)

[sritchie]

This PR:

• adds .pre-commit-config.yaml with hooks for ruff, pyright and other various helpful tidying tasks
• adds a separate ruff github action, so ruff linting callouts are added to the GitHub PR view
• pyright runs in a separate action (not pre-commit.ci) so that we can set up the poetry venv correctly (we can't do this on the pre-commit.ci server)
• makes the first batch of automatic fixes suggested by the pre-commit hooks

[sritchie]

@mhuebert it would be great to get the tests in CI as well! Take a look at the errors... the remaining ruff errors look like real bugs, yeah?

[linear]

GEN-279 Add pre-commit hooks for Ruff, Pyright to GenStudio

We should get the same affordances that we have at GenJAX.

[mhuebert]

Thanks! I have merged these changes here: #5