fix(CI): resolve remaining lint/format violations in PR #8722

- Apply ruff format to features/steps/strategize_decision_recording_steps.py:
  expanded single-line set literal to multi-line canonical form (PEP 87)
  This was the sole remaining CI lint blocker per review cycle 14.

- Remove unused imports from tests/actor/test_registry_builtin_yaml.py:
  removed 'Settings' and 'ProviderRegistry' to fix F401 errors.
  These were pre-existing violations caught by ruff check.

ISSUES CLOSED: #8522

Closes: #8722

features/steps/strategize_decision_recording_steps.py

@@ -320,7 +320,12 @@ def step_then_decision_phase(context, phase):
     """
     assert context.last_decision is not None
     # Strategize-phase decision types accepted by the hook
-    strategize_types = {"strategy_choice", "resource_selection", "subplan_spawn", "invariant_enforced"}
+    strategize_types = {
+        "strategy_choice",
+        "resource_selection",
+        "subplan_spawn",
+        "invariant_enforced",
+    }
     assert context.last_decision.decision_type.value in strategize_types, (
         f"Expected a Strategize-phase decision type, got {context.last_decision.decision_type.value!r}"
     )

tests/actor/test_registry_builtin_yaml.py

@@ -17,13 +17,12 @@ import yaml
 
 from cleveragents.actor.registry import ActorRegistry
 from cleveragents.actor.schema import ActorConfigSchema, ActorType, is_v3_yaml
-from cleveragents.config.settings import ProviderDefaults, Settings
+from cleveragents.config.settings import ProviderDefaults
 from cleveragents.core.exceptions import NotFoundError
 from cleveragents.domain.models.core.actor import Actor
 from cleveragents.providers.registry import (
     ProviderCapabilities,
     ProviderInfo,
-    ProviderRegistry,
     ProviderType,
 )