feat(harness): workflow.yaml as single source of truth + workflow.py loader (F2)
- workflow.yaml: 8-phase definition, data-driven prerequisites, no hardcoded ladder
- workflow.py: load_workflow() reader; max_phase=len(phases), decision_min_phase
derived from prerequisites scan (no duplication)
- 6 tests: phase count, decision_min_phase derivation, name lookup (incl. F8
presence -- the JS drift bug structurally impossible now), artifacts_out,
advance strategy, schema_version. All 8 harness tests pass.
marcopan
4a1272fa0a