Telescopetest-io: consider scheduling clean up for 'UNSAFE' R2 files

Maybe we can delete `content_rating`='UNSAFE' files from production R2 after we determine the unsafe rating, or delete them on a some kind of cleanup schedule. Nobody should be able to read these files anyways, so there may not be any point in keeping. We could use these R2 files for some kind of logging or debugging, hence the schedule.

No files, tests, or entry points are named. First trace how content_rating='UNSAFE' files reach production R2 and where their retention is controlled; clarify whether deletion should happen immediately or on a schedule, then define a verifiable cleanup policy without exposing these files.

Written by the indexing model from the issue text.