await-mergelisted

# Await Merge 1. **Target.** The number or URL in `$ARGUMENTS`, else the PR of the current branch: `gh pr view <n> --json number,title,url,baseRefName,commits`. None found: stop and ask for the number. 2. **Strategy.** Squash: the commits become one. `--rebase` in `$ARGUMENTS`: the commits land as they are, for a branch whose every commit is atomic. No question; the caller knows its commits. Never a merge commit; the history stays linear. 3. **Watch.** `gh pr checks <n> --watch --fail-fast`. A failing check: report its name and stop. No retry, no merge. No checks reported: say so and continue. `--dry-run`: print the target, the strategy, the commit subjects and the check state, then stop. The watch is the fact the merge depends on, so the preview includes it. 4. **Merge.** `gh pr merge <n> --squash|--rebase --delete-branch`. An error: report it verbatim and stop. A merge has no undo short of a revert, so the target is never guessed: step 1 takes the number from `$ARGUMENTS` or from the current branch, nothing else. 5. **Local.** `git switch <baseRefName>` then `git pull --ff-only`. 6. **Report.** The PR URL, the strategy, the new tip of the base branch.