fix(source-control): babysit --auto on a merge-queue base reports auto-merge enabled, not queued

[kyle-sexton]

Problem

babysit's --auto path still runs gh pr merge --auto --squash --match-head-commit. On a branch that requires a merge queue, gh enables auto-merge/enqueues, and the result reads autoMergeEnabled while the PR sits in the queue. Telemetry that assumes "merged" misreads it.

Evidence

• plugins/source-control/skills/babysit-prs/scripts/babysit_merge.py:22 ("every --auto arm keeps gh pr merge") and the --auto arm near line 2048.
• Merge queue behavior: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/incorporating-changes-from-a-pull-request/merging-a-pull-request-with-a-merge-queue

Suggested fix

On a queue base, report queued and confirm the merged state on later cycles, as the async enqueue path does.

Found while working on #5935.