ycb_django_pr14500

what a new run launched now would send

Squashed migration is not marked as unapplied
Description
	 
		(last modified by Markus Holtermann)
	 
When unapplying a squashed migration and the replaced migration files are still around, the MigrationExecutor mark the squash migration as unapplied, too, not only the replaced migrations.

Work only inside this repository checkout. Make the code change the task
describes, keeping the diff focused — no drive-by refactors.

When you are done, leave your changes committed or in the working tree;
they are collected automatically.

Stay on this snapshot checkout (`task/ycb_django_pr14500`). Never checkout, pull, or rebase onto `main`. That branch is a README-only orphan.
Stay on this HEAD. Do not fetch another default branch. Push only on the Cursor-created `crazy-cursor/…` side branch from this HEAD.

Some past runs of this task were launched with a different prompt (the prompt template changed since, or those runs predate this benchmark's stored prompt). Each run persists the exact prompt it sent at launch — that per-launch record is the audit trail; this page shows only the current one.