fix(workflow): enforce domain state machine in dual validation path

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.

backend/app/services/test_workflow_service.py

@@ -333,26 +333,14 @@ def validate_as_red_lead(
 ) -> Test:
     """Record Red Lead's validation decision.
 
-    *validation_status* must be ``"approved"`` or ``"rejected"``.
-    After recording the decision, :func:`check_dual_validation` is called
-    to potentially advance the test to ``validated`` or ``rejected``.
+    Delegates validation rules and state mutation entirely to
+    :meth:`TestEntity.validate_red`.  If both leads have voted the
+    entity will also advance the test to ``validated`` or ``rejected``.
     """
-    current = test.state.value if isinstance(test.state, TestState) else test.state
-    if test.state not in (TestState.in_review,):
-        raise InvalidOperationError(
-            f"Cannot validate red side while test is in '{current}' state (must be in_review)"
-        )
-
-    if validation_status not in ("approved", "rejected"):
-        raise InvalidOperationError(
-            "validation_status must be 'approved' or 'rejected'"
-        )
-
-    now = datetime.utcnow()
-    test.red_validation_status = validation_status
-    test.red_validated_by = user.id
-    test.red_validated_at = now
-    test.red_validation_notes = notes
+    entity = TestEntity.from_orm(test)
+    entity.validate_red(validation_status, by=user.id, notes=notes)
+    entity.apply_to(test)
+    db.flush()
 
     log_action(
         db,
@@ -367,7 +355,7 @@ def validate_as_red_lead(
         },
     )
 
-    check_dual_validation(db, test)
+    _dispatch_dual_validation_effects(db, test, entity)
     return test
 
 
@@ -380,26 +368,14 @@ def validate_as_blue_lead(
 ) -> Test:
     """Record Blue Lead's validation decision.
 
-    *validation_status* must be ``"approved"`` or ``"rejected"``.
-    After recording the decision, :func:`check_dual_validation` is called
-    to potentially advance the test to ``validated`` or ``rejected``.
+    Delegates validation rules and state mutation entirely to
+    :meth:`TestEntity.validate_blue`.  If both leads have voted the
+    entity will also advance the test to ``validated`` or ``rejected``.
     """
-    current = test.state.value if isinstance(test.state, TestState) else test.state
-    if test.state not in (TestState.in_review,):
-        raise InvalidOperationError(
-            f"Cannot validate blue side while test is in '{current}' state (must be in_review)"
-        )
-
-    if validation_status not in ("approved", "rejected"):
-        raise InvalidOperationError(
-            "validation_status must be 'approved' or 'rejected'"
-        )
-
-    now = datetime.utcnow()
-    test.blue_validation_status = validation_status
-    test.blue_validated_by = user.id
-    test.blue_validated_at = now
-    test.blue_validation_notes = notes
+    entity = TestEntity.from_orm(test)
+    entity.validate_blue(validation_status, by=user.id, notes=notes)
+    entity.apply_to(test)
+    db.flush()
 
     log_action(
         db,
@@ -414,43 +390,52 @@ def validate_as_blue_lead(
         },
     )
 
-    check_dual_validation(db, test)
+    _dispatch_dual_validation_effects(db, test, entity)
     return test
 
 
 def check_dual_validation(db: Session, test: Test) -> Test:
     """Evaluate both leads' decisions and advance the test if both have voted.
 
-    - Both **approved** → ``validated``
-    - Either **rejected** → ``rejected``
-    - Otherwise no state change (waiting for the other lead).
-
-    Commits only when the state actually changes.
+    All state mutation is delegated to :meth:`TestEntity.check_dual_validation`.
+    This function never assigns ``test.state`` directly.
     """
-    red_status = test.red_validation_status
-    blue_status = test.blue_validation_status
+    entity = TestEntity.from_orm(test)
+    entity.check_dual_validation()
+    entity.apply_to(test)
 
-    if red_status == "rejected" or blue_status == "rejected":
-        test.state = TestState.rejected
-        try:
-            notify_test_state_change(db, test, "rejected")
-        except Exception as e:
-            logger.warning("Notification failed for test %s (rejected): %s", test.id, e, exc_info=True)
-    elif red_status == "approved" and blue_status == "approved":
-        test.state = TestState.validated
-        # Invalidate cached scores — a validation changes org-level numbers
-        try:
-            from app.services.score_cache import invalidate
-            invalidate()
-        except Exception as e:
-            logger.warning("Score cache invalidation failed: %s", e, exc_info=True)
-        try:
-            notify_test_state_change(db, test, "validated")
-        except Exception as e:
-            logger.warning("Notification failed for test %s (validated): %s", test.id, e, exc_info=True)
+    _dispatch_dual_validation_effects(db, test, entity)
     return test
 
 
+def _dispatch_dual_validation_effects(
+    db: Session, test: Test, entity: TestEntity
+) -> None:
+    """Dispatch side effects (notifications, cache) based on domain events."""
+    for event in entity.events:
+        if event.name == "dual_validation_approved":
+            try:
+                from app.services.score_cache import invalidate
+                invalidate()
+            except Exception as e:
+                logger.warning("Score cache invalidation failed: %s", e, exc_info=True)
+            try:
+                notify_test_state_change(db, test, "validated")
+            except Exception as e:
+                logger.warning(
+                    "Notification failed for test %s (validated): %s",
+                    test.id, e, exc_info=True,
+                )
+        elif event.name == "dual_validation_rejected":
+            try:
+                notify_test_state_change(db, test, "rejected")
+            except Exception as e:
+                logger.warning(
+                    "Notification failed for test %s (rejected): %s",
+                    test.id, e, exc_info=True,
+                )
+
+
 def handle_remediation_completed(db: Session, test: Test, user: User) -> Test | None:
     """Create a re-test when remediation is completed.