#382 CLEANUP: Remove deprecated SchedulerService (superseded by durable_cron)

SchedulerService and scheduler_worker.py are dead code. durable_cron (Issue #19) supersedes them completely. Files to remove: - engine/services/scheduler_service.py - engine/cli/scheduler_worker.py - scripts/test-scheduler-setup.sh (SchedulerService references) The schedules.py API already uses durable_cron exclusively (see lines 1-12 architecture note).