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

nisse-dev/tests/test_llm.py

@@ -184,8 +184,8 @@ def test_malformed_response_raises_llm_error() -> None:
 ROLES = RoleMap(
     executor="local/qwen",
     planner="anthropic/claude-opus-5",
-    delegate="anthropic/claude-opus-5",
-    consultant="anthropic/claude-opus-5",
+    helper="anthropic/claude-opus-5",
+    expert="anthropic/claude-opus-5",
 )
 
 
@@ -195,8 +195,8 @@ def test_role_map_resolves_and_pins() -> None:
     assert roles.pinned() == {
         "executor": "local/qwen",
         "planner": "anthropic/claude-opus-5",
-        "delegate": "anthropic/claude-opus-5",
-        "consultant": "anthropic/claude-opus-5",
+        "helper": "anthropic/claude-opus-5",
+        "expert": "anthropic/claude-opus-5",
     }