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/views.py

@@ -38,10 +38,8 @@ NARRATION_RESULT_CHARS = 300
 # The roles whose work the viewer is shown, and how: "report" keeps only the
 # handback, "narrate" keeps a line per step. Anything not listed is not shown.
 _SHOWN: dict[str, dict[str, str]] = {
-    "planner": {},
     "driver": {"helper": "report"},
-    "executor": {"helper": "report"},
-    "helper": {"executor": "narrate", "driver": "narrate"},
+    "helper": {"driver": "narrate"},
 }
 
 
@@ -101,8 +99,8 @@ def project(events: list[StoredEvent], viewer: str) -> list[StoredEvent]:
     for stored in events:
         event, actor = stored.event, stored.actor
         if isinstance(event, PlanSubmitted):
-            # A record for the executor's scope and the dump, not a turn:
-            # the planner's own submit_plan call already carries the plan.
+            # A record for a helper's scope and the dump, not a turn: the
+            # driver's own call already carries what was agreed.
             if viewer == "helper":
                 out.append(_said(stored, "approved plan", event.plan))
             continue