shall be limited to situations in which such confinement— (A) is limited to the briefest term and the least restrictive conditions practicable, including not less than 4 hours of out-of-cell time every day, which may include work assignments, staff-led programs, peer-led programs, volunteer programs, time in a day room or recreation area with at least several other people, meals, or other similar congregate activities with at least several other people in a group setting conducive to meaningful human interaction, unless the inmate poses a substantial and immediate threat