hooks: retained pre_start containers removed before service containers on compose down -v #14109

This issue was filed by an AI agent on a human's behalf. The human submitter may not have independently verified the report.

removePreStartHookContainers is called before service containers are stopped in down() (PR #14091, down.go:110). Hook containers share volumes with the service container via VolumesFrom. Removing them with -v before stopping the service container may cause volume leaks if the service container holds anonymous volume references.

Suggested fix: move the hook-container sweep to after service container removal, or at minimum verify the ordering is safe.

Mentioned in #14091 review by @ndeloof (down.go:110).