ci(Repo): Add claude GitHub actions

[risixdzn]

Adds two GitHub Actions workflows that wire the Claude Code action into the repository. Both authenticate with the CLAUDE_CODE_OAUTH_TOKEN secret and only ever read from the repo: neither can push, comment on issues or open a PR.

claude.yml (PR assistant)

Runs on demand. It fires on issue comments, PR review comments, PR reviews and opened/assigned issues, and the job is gated on the body (or issue title) containing @claude, so nothing runs unless someone asks for it.

It is granted actions: read on top of the usual read scopes so it can look at CI results when answering about a failing PR.

claude-code-review.yml (automatic review)

Runs on every opened, synchronize, ready_for_review and reopened pull request. It loads the code-review plugin from the upstream marketplace and runs /code-review --comment, which leaves inline comments on the diff. --allowedTools is pinned to the inline comment tool alone, so the job cannot do anything beyond commenting.

Before merging

CLAUDE_CODE_OAUTH_TOKEN has to exist as a repository secret, otherwise both jobs fail on the action step.

Worth deciding as a team: the review workflow runs on every PR, including drafts once they are marked ready. If that turns out to be noisy, the commented-out paths filter and author filter already in the file are the knobs to narrow it down.

How to test

1. Comment @claude on this PR and confirm the Claude Code workflow picks it up.
2. Push a commit here and confirm Claude Code Review runs and leaves inline comments.