Rename the delegate and consultant roles to helper and expert

Architecture L9's role names, for the two roles with a direct
counterpart: the delegation role is now 'helper' and the ask_expert role
'expert', in RoleMap, configuration (roles.helper, roles.expert),
recorded events and tests. 'planner' and 'executor' stay distinct for
now; they become 'driver' when the new loop merges them (Development
Plan M2.3).

Configurations must rename their keys: nisse-dev.example.yaml and
tests/integration/nisse-test.yaml are updated here.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPQ14L3LikyefCMFBqEbKE

tests/integration/test_expert_live.py

@@ -22,7 +22,7 @@ pytestmark = pytest.mark.integration
 def desk(tmp_path: Path, litellm: LiteLLMClient, live_model: str):
     def make(budget: int = 2) -> tuple[ExpertDesk, StateStore]:
         model = live_model
-        roles = RoleMap(executor=model, planner=model, delegate=model, consultant=model)
+        roles = RoleMap(executor=model, planner=model, helper=model, expert=model)
         store = StateStore(
             tmp_path / "state.db", oplog=OpLog("nisse-dev", io.StringIO())
         )
@@ -43,7 +43,7 @@ def test_live_consult_parses_against_the_local_schema(desk) -> None:
     assert len(answer.answer) > 20
     # The consult is captured for L9 without any extra bookkeeping.
     [record] = collect(store)
-    assert record.role == "consultant"
+    assert record.role == "expert"
     assert record.exit_status == "answered"