Function approve 

pub fn approve(pr_number: usize) -> Result<()>

Approve a pull request via gh pr review --approve.

Issues an approval review for the specified pull request using the GitHub CLI. Mirrors the minimalist style of merge for consistency and keeps policy / flag decisions localized here.

Errors

• Spawning or executing gh pr review fails.
• Command exits with non‑zero status (propagated by [ytil_cmd::CmdExt]).