M2.8: switch over to the new loop

nisse-dev now runs only the conversational loop. The gated state machine
it was built alongside is gone:

- Removed control.py, planner.py, executor.py, approvals.py, gates.py
  (command_form moves to loop/reader.py), publish.py and poller.py, the
  old assembly in agent.py (its shared helpers move to loop/build.py),
  the store's state-machine view (get_state, transition), their tests,
  the old end-to-end and live planning/milestone/gate tests, and
  specs/orchestrator.qnt with its scenarios.
- Roles are driver, helper, expert and classifier; driver is required.
  loop:, roles.planner, roles.executor and tuning.executor are refused
  with what to use instead; tuning.driver takes the turn cap and failure
  limit.
- The benchmark and the capability matrix measure the driver: the
  loop's own system prompt and tools, the task's plan as the agreed
  restatement. Task plans end with finish_milestone, so earlier runs
  show as (old); stored runs' executor tuning reads as the driver's.
- A delegation on the loop records what its helper's alias resolved to
  (L9), as the old path's did.
- The dump shows a work item's revision and what it waits for.
- Behaviour the old tests covered and the loop shares stays covered:
  driver runs that fail on a model call, stop mid-turn, reset the
  failure count; go-aheads ignoring case and punctuation; a request too
  big to fit is never sent; the assembly tests, now on build_loop_agent.

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

nisse-dev/src/nisse_dev/llm.py

@@ -114,22 +114,13 @@ class LLMClient(Protocol):
 
 @dataclass(frozen=True)
 class RoleMap:
-    executor: str  # the old loop's (control.py), until M2.8
-    planner: str  # the old loop's, until M2.8
+    driver: str  # drives the loop (L2)
     helper: str  # delegations (L9)
     expert: str  # ask_expert (L9)
-    driver: str = ""  # drives the new loop; unset, the planner's model
     classifier: str = ""  # reads go-aheads now, actions later (L4); unset, expert's
 
-    ROLES: ClassVar[tuple[str, ...]] = (
-        "executor",
-        "planner",
-        "helper",
-        "expert",
-        "driver",
-        "classifier",
-    )
-    _FALLBACK: ClassVar[dict[str, str]] = {"driver": "planner", "classifier": "expert"}
+    ROLES: ClassVar[tuple[str, ...]] = ("driver", "helper", "expert", "classifier")
+    _FALLBACK: ClassVar[dict[str, str]] = {"classifier": "expert"}
 
     def resolve(self, role: str) -> str:
         if role not in self.ROLES: