Add pre-commit hook `shellcheck-py` to standardize shell files

https://github.com/shellcheck-py/shellcheck-py

https://www.shellcheck.net/

https://github.com/koalaman/shellcheck

Example `.pre-commit-config.yaml` entry:

```
- repo: https://github.com/shellcheck-py/shellcheck-py
rev: v0.10.0.1
hooks:
- id: shellcheck
```

Example `.shellcheckrc` config file:

```
disable=SC2004,SC2041,SC2155,SC2181
```

Start by locating the repository's .pre-commit-config.yaml and reviewing how existing hooks are organized. Add the shellcheck-py hook using the example revision and id, and determine whether the shown .shellcheckrc settings belong in the repository; done means shell files are covered by the configured hook.

Written by the indexing model from the issue text.