fix(context-policy): resolve AmbiguousStep conflict and fix ruff formatting

Rename step decorators in context_policy_strategy_config_steps.py from
'the strategy should be "{strategy}"' to 'the policy strategy should be
"{strategy}"' (and likewise for the None variant) to avoid collision with
the identically-patterned step already registered in
plan_merge_strategy_steps.py. Update the feature file to match.

Also apply ruff format to the three files flagged by CI lint gate:
- features/steps/context_policy_strategy_config_steps.py
- scripts/update_context_policy.py
- src/cleveragents/domain/models/core/context_policy.py

ISSUES CLOSED: #7572

features/context_policy_strategy_config.feature

@@ -7,31 +7,31 @@ Feature: Context Policy Strategy Configuration
   Scenario: Create context policy with basic strategy
     Given a context policy with strategy "basic"
     When I validate the context policy
-    Then the strategy should be "basic"
+    Then the policy strategy should be "basic"
     And the policy should be valid
 
   Scenario: Create context policy with semantic strategy
     Given a context policy with strategy "semantic"
     When I validate the context policy
-    Then the strategy should be "semantic"
+    Then the policy strategy should be "semantic"
     And the policy should be valid
 
   Scenario: Create context policy with relevance_scoring strategy
     Given a context policy with strategy "relevance_scoring"
     When I validate the context policy
-    Then the strategy should be "relevance_scoring"
+    Then the policy strategy should be "relevance_scoring"
     And the policy should be valid
 
   Scenario: Create context policy with adaptive strategy
     Given a context policy with strategy "adaptive"
     When I validate the context policy
-    Then the strategy should be "adaptive"
+    Then the policy strategy should be "adaptive"
     And the policy should be valid
 
   Scenario: Create context policy with fusion strategy
     Given a context policy with strategy "fusion"
     When I validate the context policy
-    Then the strategy should be "fusion"
+    Then the policy strategy should be "fusion"
     And the policy should be valid
 
   Scenario: Reject invalid strategy name
@@ -50,7 +50,7 @@ Feature: Context Policy Strategy Configuration
   Scenario: Create context policy without strategy
     Given a context policy without strategy
     When I validate the context policy
-    Then the strategy should be None
+    Then the policy strategy should be None
     And the policy should be valid
 
   Scenario: Create context policy with strategy but no config

features/steps/context_policy_strategy_config_steps.py

@@ -63,7 +63,7 @@ def step_validate_policy(context: Context) -> None:
         context.policy_error = str(exc)
 
 
-@then('the strategy should be "{strategy}"')
+@then('the policy strategy should be "{strategy}"')
 def step_strategy_is(context: Context, strategy: str) -> None:
     if strategy == "None":
         assert context.policy.strategy is None
@@ -71,14 +71,16 @@ def step_strategy_is(context: Context, strategy: str) -> None:
         assert context.policy.strategy == strategy
 
 
-@then("the strategy should be None")
+@then("the policy strategy should be None")
 def step_strategy_is_none(context: Context) -> None:
     assert context.policy.strategy is None
 
 
 @then("the policy should be valid")
 def step_policy_valid(context: Context) -> None:
-    assert context.policy_error is None, f"Expected valid policy but got error: {context.policy_error}"
+    assert context.policy_error is None, (
+        f"Expected valid policy but got error: {context.policy_error}"
+    )
 
 
 @then("the policy should be invalid")