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

tests/integration/test_benchmark_live.py

@@ -1,16 +1,16 @@
 """One live benchmark run: the simplest task, through the agent's own
-client wiring, with the test config's executor."""
+client wiring, with the test config's driver."""
 
 from pathlib import Path
 
 import pytest
 
-from nisse_dev.agent import make_llm_clients
 from nisse_dev.bench.runner import run_task
 from nisse_dev.bench.tasks import load_tasks
 from nisse_dev.catalog import ModelCatalog
 from nisse_dev.config import AgentConfig
 from nisse_dev.execution import SSHHost
+from nisse_dev.loop.build import make_llm_clients
 
 pytestmark = pytest.mark.integration
 
@@ -20,7 +20,7 @@ def test_the_simplest_task_passes_live(
 ) -> None:
     catalog = ModelCatalog.discover(live_config.llm_base_url, live_config.llm_token)
     normalized, _ = make_llm_clients(live_config, catalog)
-    facts = catalog.facts(live_config.roles.executor)
+    facts = catalog.facts(live_config.roles.driver)
     [task] = load_tasks(["write-function"])
 
     record = run_task(