BE-CAL-001: Add TimeSlot model with SlotType/SlotStatus/EventType enums
- New calendar.py model file with TimeSlot table definition
- SlotType enum: work, on_call, entertainment, system
- SlotStatus enum: not_started, ongoing, deferred, skipped, paused, finished, aborted
- EventType enum: job, entertainment, system_event
- All fields per design doc: user_id, date, slot_type, estimated_duration,
scheduled_at, started_at, attended, actual_duration, event_type, event_data (JSON),
priority, status, plan_id (FK to schedule_plans)
zhi
3dcd07bdf3