- New Propose model (app/models/propose.py) with status enum (open/accepted/rejected) - New Propose schemas (ProposeCreate/Update/Response) in schemas.py - MySQL enum migration in main.py for milestone/task status columns - milestone: pending→open, deferred→closed, progressing→undergoing - task: progressing→undergoing - Import propose model in startup for create_all - Add started_at column migration for milestones