test_expert: a declined consult hands back the clients' real wording

The fake client raises _refused() from llm.py, and the test checks the
whole handback, so a change to the real message fails it (review on #165).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk

nisse-core/tests/test_expert.py

@@ -18,7 +18,7 @@ from nisse_core.loop.expert import (
     ExpertDesk,
     parse_answer,
 )
-from nisse_core.models.llm import LLMError, ModelRefused, RoleMap
+from nisse_core.models.llm import LLMError, RoleMap, _refused
 from nisse_core.oplog import OpLog
 from nisse_core.state.store import Transcript
 from nisse_dev.state import StateStore
@@ -147,7 +147,7 @@ class DecliningClient(ScriptedClient):
 
     def complete(self, events: Any, tools: Any, model: str, system: Any = None) -> Any:
         self.calls.append({"model": model, "system": system})
-        raise ModelRefused(f"{model} declined to answer: its provider's safety filter")
+        raise _refused(model)  # the clients' own wording
 
 
 def test_a_declined_question_is_not_asked_again_and_says_why(
@@ -162,7 +162,11 @@ def test_a_declined_question_is_not_asked_again_and_says_why(
         e.event for e in log(store).read() if isinstance(e.event, DelegationCompleted)
     ]
     assert completed.exit_status == "failed"
-    assert "safety filter" in completed.handback
+    assert completed.handback == (
+        "claude-haiku-4-5 declined to answer: its provider's safety filter stopped the "
+        "reply. That says nothing about the subject itself. Ask it "
+        "differently, or work from the repository"
+    )
 
 
 def test_retry_succeeds_after_a_bad_first_reply(store: StateStore) -> None: