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/e2e_support.py

@@ -10,6 +10,8 @@ from collections.abc import Iterator
 from dataclasses import dataclass
 from pathlib import Path
 
+from nisse_dev.config import BuildHost
+from nisse_dev.execution import SSHHost
 from nisse_dev.gitea import GiteaClient, GiteaError
 from nisse_dev.llm import RoleMap
 
@@ -23,7 +25,7 @@ E2E_MODEL = "qwen3.8-27b-nothink"
 
 def e2e_roles() -> RoleMap:
     model = os.environ.get("NISSE_E2E_MODEL", "").strip() or E2E_MODEL
-    return RoleMap(executor=model, planner=model, helper=model, expert=model)
+    return RoleMap(driver=model, helper=model, expert=model)
 
 
 def task(run: str) -> str:
@@ -177,3 +179,18 @@ def fresh_repo(
     finally:
         if not os.environ.get("NISSE_E2E_KEEP_REPOS"):
             delete_repo(operator, repo.name)
+
+
+def build_host(ssh_host: SSHHost) -> BuildHost:
+    """The operator's build VM when scripts/e2e.sh names one, otherwise the
+    throwaway local sshd."""
+    address = os.environ.get("NISSE_E2E_BUILD_HOST")
+    if address:
+        key = Path(os.environ["NISSE_E2E_BUILD_KEY"])
+        return BuildHost(address=address, key=key)
+    return BuildHost(
+        address=ssh_host.address,
+        key=ssh_host._key,
+        user=ssh_host.user,
+        port=ssh_host.port,
+    )