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/state.py

@@ -12,7 +12,6 @@ resolved against external truth on boot).
 
 import json
 import sqlite3
-import uuid
 from collections.abc import Callable, Mapping
 from dataclasses import dataclass
 from datetime import UTC, datetime
@@ -42,10 +41,9 @@ Migration = Callable[[sqlite3.Connection], None]
 # Maps version N to the migration that takes the schema from N to N+1.
 MIGRATIONS: Mapping[int, Migration] = {}
 
-IDLE = "IDLE"
-
 # Who produced an event (L7): the operator, the orchestrator's own code, or a
-# model role (L9). planner and executor become driver in the new loop (M2.3).
+# model role (L9). planner and executor are the old loop's (until M2.8), kept
+# so its records still read.
 ACTORS = frozenset(
     {
         "operator",
@@ -64,17 +62,6 @@ class StateSchemaError(RuntimeError):
     pass
 
 
-@dataclass(frozen=True)
-class AgentState:
-    """The state machine's view of the active work item (control.py, until
-    Development Plan M2.6 retires it)."""
-
-    state: str
-    project: str | None
-    data: dict[str, Any]
-    updated_at: str
-
-
 @dataclass(frozen=True)
 class WorkItem:
     id: str
@@ -406,61 +393,6 @@ class StateStore:
             )
         return len(rows)
 
-    # --- the state machine's view (control.py, until M2.6) -----------------
-
-    def get_state(self) -> AgentState | None:
-        """The active work item as the state machine sees it: its position
-        is the state, IDLE when there is none. None only for a store the
-        agent has never started on."""
-        agent = self._conn.execute("SELECT * FROM agent WHERE id = 1").fetchone()
-        if agent is None:
-            return None
-        item = self.active_item()
-        if item is None:
-            return AgentState(IDLE, None, {}, agent["updated_at"])
-        return AgentState(item.position, item.scope, item.data, item.updated_at)
-
-    def transition(
-        self,
-        state: str,
-        *,
-        cause: str,
-        project: str | None = None,
-        data: dict[str, Any] | None = None,
-    ) -> None:
-        """The state machine's transition, over work items: IDLE closes and
-        deactivates the active item (its outcome should already be recorded
-        with close_work_item); any other state updates the active item,
-        opening one if there is none."""
-        self._ensure_agent_row()
-        active = self.active_item()
-        if state == IDLE:
-            if active is not None:
-                if active.status == "open":
-                    self.close_work_item(active.id, outcome="closed", cause=cause)
-                self.set_active(None, cause=cause)
-            self.oplog.emit(
-                "state.transition",
-                cause=cause,
-                **{
-                    "from": active.position if active else None,
-                    "to": IDLE,
-                    "project": project,
-                },
-            )
-            return
-        if active is None:
-            item_id = str((data or {}).get("task_id") or f"task-{uuid.uuid4().hex[:8]}")
-            active = self.open_work_item(
-                item_id,
-                title=project or item_id,
-                scope=project,
-                position=IDLE,
-                cause=cause,
-            )
-            self.set_active(item_id, cause=cause)
-        self.update_work_item(active.id, position=state, data=data or {}, cause=cause)
-
     # --- intents (L8) ------------------------------------------------------
 
     def begin_intent(