Iterate on PR Feedback

Fetch review comments, address each issue, and request re-review.

Workflow

1. Identify PR - Get PR number from branch or argument
2. Fetch review comments - Get all unresolved feedback
3. Address each comment - Fix issues, apply suggestions
4. Commit and push - Save changes to PR branch
5. Request re-review - Comment with configurable review command

Step 1: Identify PR

If $ARGUMENTS is provided, use it as the PR number. Otherwise, detect from current branch:

gh pr view --json number --jq '.number'