fix(domain): replace type: ignore suppressions with setattr in immutability tests

Replace all # type: ignore[misc] reassignment checks in
features/steps/domain_model_immutability_steps.py with setattr() calls
to exercise frozen model enforcement without suppressing type errors.

Add B010 to per-file-ignores for features/steps/*.py in pyproject.toml
since setattr with constant attribute names is intentional in immutability
tests (exercises frozen Pydantic model enforcement).

Update CONTRIBUTORS.md to document HAL 9000 contributions.

ISSUES CLOSED: #7553

features/steps/domain_model_immutability_steps.py

@@ -100,7 +100,7 @@ def step_attempt_reassign_plan_id(context: Context) -> None:
     """Attempt to reassign plan_id on a frozen PlanIdentity."""
     context.immut_error = None
     try:
-        context.immut_plan.identity.plan_id = _VALID_ULID_2  # type: ignore[misc]
+        setattr(context.immut_plan.identity, "plan_id", _VALID_ULID_2)
     except (ValidationError, TypeError) as exc:
         context.immut_error = exc
 
@@ -142,7 +142,7 @@ def step_attempt_reassign_root_plan_id(context: Context) -> None:
     """Attempt to reassign root_plan_id on a frozen PlanIdentity."""
     context.immut_error = None
     try:
-        context.immut_plan.identity.root_plan_id = _VALID_ULID_ROOT  # type: ignore[misc]
+        setattr(context.immut_plan.identity, "root_plan_id", _VALID_ULID_ROOT)
     except (ValidationError, TypeError) as exc:
         context.immut_error = exc
 
@@ -270,7 +270,7 @@ def step_attempt_reassign_action_name(context: Context) -> None:
     """Attempt to reassign the action's namespaced_name.name."""
     context.immut_error = None
     try:
-        context.immut_action.namespaced_name.name = "new-name"  # type: ignore[misc]
+        setattr(context.immut_action.namespaced_name, "name", "new-name")
     except (ValidationError, TypeError) as exc:
         context.immut_error = exc
 
@@ -301,7 +301,7 @@ def step_attempt_reassign_action_namespace(context: Context) -> None:
     """Attempt to reassign the action's namespaced_name.namespace."""
     context.immut_error = None
     try:
-        context.immut_action.namespaced_name.namespace = "neworg"  # type: ignore[misc]
+        setattr(context.immut_action.namespaced_name, "namespace", "neworg")
     except (ValidationError, TypeError) as exc:
         context.immut_error = exc
 
@@ -394,7 +394,7 @@ def step_attempt_reassign_plan_namespaced_name(context: Context) -> None:
     """Attempt to reassign the plan's namespaced_name.name."""
     context.immut_error = None
     try:
-        context.immut_plan.namespaced_name.name = "new-name"  # type: ignore[misc]
+        setattr(context.immut_plan.namespaced_name, "name", "new-name")
     except (ValidationError, TypeError) as exc:
         context.immut_error = exc
 
@@ -413,7 +413,7 @@ def step_attempt_reassign_plan_namespaced_namespace(context: Context) -> None:
     """Attempt to reassign the plan's namespaced_name.namespace."""
     context.immut_error = None
     try:
-        context.immut_plan.namespaced_name.namespace = "neworg"  # type: ignore[misc]
+        setattr(context.immut_plan.namespaced_name, "namespace", "neworg")
     except (ValidationError, TypeError) as exc:
         context.immut_error = exc
 

pyproject.toml

@@ -128,7 +128,8 @@ ignore = []
 [tool.ruff.lint.per-file-ignores]
 "__init__.py" = ["F401"]
 # Behave step files: F811 = redefined step_impl (Behave pattern), E501 = long step decorator strings
-"features/steps/*.py" = ["F811", "E501"]
+# B010 = setattr with constant attribute name is intentional in immutability tests (exercises frozen model enforcement)
+"features/steps/*.py" = ["F811", "E501", "B010"]
 "features/mocks/*.py" = ["E501"]
 "features/environment.py" = ["E501"]
 # retry_patterns.py re-exports symbols from retry_service_patterns at module bottom