chore: add pre-commit config

[nanomad]

Summary

Adds a `.pre-commit-config.yaml` so contributors can run the same checks the CI workflow runs (`mypy`, `ruff check`, `pytest`) before pushing. Mirrors the setup in the sister repo `saic-python-client-ng` so the two projects stay consistent.

Hooks

Stage	Hooks
pre-commit	`poetry-check`, `poetry-lock`, `ruff` (with `--fix --unsafe-fixes`), `ruff-format`, `mypy`, `check-yaml`, `check-added-large-files`
pre-push	`pytest tests`

Deliberate differences vs. `saic-python-client-ng`

• No `pylint` — this repo dropped pylint in favour of ruff and mypy in 0.10.0.
• `pytest` is wired to `pre-push` rather than skipped entirely. Commits stay fast; pushes verify the test suite. Locally CI-equivalent without waiting for GitHub.

To enable locally

```
pipx install pre-commit
pre-commit install --hook-type pre-commit --hook-type pre-push
```

Test plan

• `pre-commit run --all-files` passes on a clean checkout
• `pre-commit run --hook-stage pre-push` runs the full pytest suite (177 tests pass)
• CI passes