Voice Sessions Cleanup

Meter and close calls that have gone quiet, by hand.

Same rules as the scheduled reaper in app/scheduler.py, and for the same reasons: a call is abandoned when it stops beating, not when it gets old (nothing caps a call's length, and charging a live call mid-call would then block the real ending from charging the rest), and the charge lands BEFORE the row leaves "active" so a failed meter retries instead of silently writing the call off. This endpoint used to do neither — it marked calls ended and never metered them at all.