Add Claude code review workflow

[mslynch]

Adds the standard claude-code-review.yaml used in prism. Triggers a review on every PR via shared workflow from posit-hosted/gha.

[mslynch]

I'm going to respond to a handful of comments that other Claudes have left on the many PRs to add this file across our repos to address review comments en masse:

issue_comment trigger will fire for all issues, not just PRs

This is acceptable for us - we'd rather have this functionality and deal with the noise than not.

the workflow SHA isn't pinned

We maintain posit-hosted/gha fully. We don't plan on releasing any breaking changes, and we trust the code entirely. In case of vulnerabilities, we'll disable the workflow in the gha repo.

How was this tested?

This has been implemented across several repos across the organization without issue.

no permissions on the workflow

The workflow defined in posit-hosted/gha has permissions defined, which we control and trust - adding permissions to this file is redundant.