validate_as_red/blue_lead now delegate to TestEntity. check_dual_validation routes through entity instead of assigning test.state directly. Side effects dispatched via domain events. Entity raises InvalidOperationError for backward compat. Removed 4 dead V1 xfail tests, fixed 2 real test issues. 224 passed, 0 xfailed.
str() on models.enums.TestState produces 'TestState.red_executing' instead of 'red_executing'. Use .value to extract the plain string before constructing the domain TestState.
transition_state() now hydrates a TestEntity from the ORM model and delegates state validation to entity.transition_to(). The entity is authoritative for which transitions are valid; VALID_TRANSITIONS and can_transition() are kept for backward compatibility.
Also adds public transition_to() method to TestEntity as the stable API surface for callers that need a single validated transition without lifecycle side-effects.
