fix(context): update plugin_extension_points tests for 31st extension point

Update plugin_extension_points.feature and step definitions to reflect
the addition of the ScopeChainResolverExtension as the 31st extension
point. The PR added the extension point but forgot to update the existing
test file that hardcoded the count as 30.

ISSUES CLOSED: #5705

features/plugin_extension_points.feature

@@ -1,21 +1,21 @@
 Feature: Plugin Extension Points Registration
-  The plugin infrastructure must register all 30 spec-defined extension
+  The plugin infrastructure must register all 31 spec-defined extension
   points with typed Protocol interfaces in the PluginManager.
 
   Based on issue #939.
 
   # -----------------------------------------------------------------------
-  # All 30 extension points are registered
+  # All 31 extension points are registered
   # -----------------------------------------------------------------------
 
-  Scenario: All 30 extension points are registered via register_all_extension_points
+  Scenario: All 31 extension points are registered via register_all_extension_points
     Given a fresh PluginManager for extension point registration
     When I register all spec-defined extension points
-    Then exactly 30 extension points should be registered
+    Then exactly 31 extension points should be registered
 
   Scenario: Extension point definitions are available as a tuple
     When I retrieve the extension point definitions
-    Then I should get exactly 30 extension point definitions
+    Then I should get exactly 31 extension point definitions
     And each definition should have a non-empty name
     And each definition should have a protocol_type
     And each definition should have a non-empty description
@@ -60,6 +60,7 @@ Feature: Plugin Extension Points Registration
     And the "event" category should have 2 extension points
     And the "config" category should have 2 extension points
     And the "safety" category should have 1 extension points
+    And the "scope" category should have 1 extension points
 
   # -----------------------------------------------------------------------
   # Protocol type correctness
@@ -93,8 +94,8 @@ Feature: Plugin Extension Points Registration
   # TOTAL_EXTENSION_POINTS constant
   # -----------------------------------------------------------------------
 
-  Scenario: TOTAL_EXTENSION_POINTS constant equals 30
-    Then the TOTAL_EXTENSION_POINTS constant should equal 30
+  Scenario: TOTAL_EXTENSION_POINTS constant equals 31
+    Then the TOTAL_EXTENSION_POINTS constant should equal 31
 
   # -----------------------------------------------------------------------
   # Context extension points wired to ACMSPipeline
@@ -125,7 +126,7 @@ Feature: Plugin Extension Points Registration
     Given a fresh PluginManager for extension point registration
     When I register all spec-defined extension points
     And I register all spec-defined extension points again
-    Then exactly 30 extension points should be registered
+    Then exactly 31 extension points should be registered
 
   # -----------------------------------------------------------------------
   # Extension point registry_key matches category
@@ -227,3 +228,8 @@ Feature: Plugin Extension Points Registration
     Given a concrete SafetyGuardrailExtension implementation
     Then it should be recognized as a SafetyGuardrailExtension instance
     And calling its guardrail methods should succeed
+
+  Scenario: A concrete scope chain resolver satisfies ScopeChainResolverExtension
+    Given a concrete ScopeChainResolverExtension implementation
+    Then it should be recognized as a ScopeChainResolverExtension instance
+    And calling its scope chain resolver methods should succeed

features/steps/plugin_extension_points_steps.py

@@ -1,6 +1,6 @@
 """Step definitions for plugin_extension_points.feature.
 
-Tests all 30 spec-defined extension points: registration, lookup
+Tests all 31 spec-defined extension points: registration, lookup
 by name, lookup by category, protocol type correctness, entry point
 discovery, context subsystem wiring, and idempotent registration.
 
@@ -37,6 +37,7 @@ from cleveragents.infrastructure.plugins.extension_protocols import (
     ResourceResolverExtension,
     ResourceTypeHandlerExtension,
     SafetyGuardrailExtension,
+    ScopeChainResolverExtension,
     SkillProviderExtension,
     SkillTemplateExtension,
     ToolMiddlewareExtension,
@@ -473,6 +474,20 @@ class _StubConfigValidator:
         return []
 
 
+class _StubScopeChainResolver:
+    @property
+    def resolver_name(self) -> str:
+        return "stub_scope_resolver"
+
+    def can_resolve(self, name: str) -> bool:
+        return name.startswith("stub:")
+
+    def resolve(self, name: str, context: Any) -> str | None:
+        if self.can_resolve(name):
+            return f"resolved_{name[5:]}"
+        return None
+
+
 class _StubSafetyGuardrail:
     @property
     def guardrail_name(self) -> str:
@@ -794,3 +809,25 @@ def step_call_safety_methods(context: Context) -> None:
     assert impl.guardrail_name == "stub_guardrail"
     assert impl.check("some_action") is True
     assert impl.explain() == "Always allows"
+
+# --- Scope Chain Resolver ---
+
+
+@given("a concrete ScopeChainResolverExtension implementation")
+def step_concrete_scope_resolver(context: Context) -> None:
+    context.ep_impl = _StubScopeChainResolver()
+
+
+@then("it should be recognized as a ScopeChainResolverExtension instance")
+def step_isinstance_scope_resolver(context: Context) -> None:
+    assert isinstance(context.ep_impl, ScopeChainResolverExtension)
+
+
+@then("calling its scope chain resolver methods should succeed")
+def step_call_scope_resolver_methods(context: Context) -> None:
+    impl = context.ep_impl
+    assert impl.resolver_name == "stub_scope_resolver"
+    assert impl.can_resolve("stub:test") is True
+    assert impl.can_resolve("other:test") is False
+    assert impl.resolve("stub:test", {}) == "resolved_test"
+    assert impl.resolve("other:test", {}) is None