Phase 6: SchemaShiftEnvironment scheduler — full episode lifecycle

Phase 5: Composable rubric grader + dense step shaping

Phase 4: CRMAPI with 3 drifts + scenarios E1/E2/E3

Phase 3: CalendarAPI with 2 drifts + DriftInjector

Phase 2: BaseTool + MailAPI with 3 drift handlers

Phase 1: Pydantic models + validation tests

first commit