feat: add allow_realtime and window config to subscriptions
Add allow_realtime (boolean) and window (days, time_start, time_end, tz)
fields to subscription schema on both client and server sides, with
migration to persist them. These fields flow through subscriptions:sync
from garden to server.
SOW-4
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>