Add executor tool loop (A12/A15) — step 5b

- tools.py: four flat tools (read_file, write_file, list_dir,
  run_command) per A15's reduced manifest. Deliberately unsandboxed:
  the VM is the trust boundary (B3) and tool use is auto-approved
  inside an approved unit of work (A4), so path confinement would add
  failure modes without adding safety. What is enforced is
  operational — timeout with process-group kill so a backgrounded
  server cannot outlive its command, output truncation so a build log
  cannot eat the context window, closed stdin so prompts fail fast,
  and a scrubbed environment so project code never sees the agent's
  credentials
- executor.py: renders the log, calls the executor role with the
  reduced manifest, dispatches tool calls, and checkpoints every
  result (A13). Escalation is observable, never self-assessed (A12):
  consecutive command failures and a hard turn cap. Failed reads do
  not count — looking around is not failing
- Until delegation exists (step 7), escalation gates to the human
  with the failures attached
- control.py: start milestone now runs the executor; a stopped
  milestone gates to AWAIT_INPUT

Two bugs found by running it live against real models:

- A turn-ending gate tool (submit_plan) left a tool_call with no
  tool_result, which providers reject outright, so every planning
  turn after the first failed with a 400. The planner now records the
  gate as the call's outcome, which is also the truthful transcript
- The renderer now emits a placeholder for any tool_call lacking a
  result, so a crash between call and result (A3) cannot poison the
  transcript permanently

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/integration/test_milestone_live.py

@@ -0,0 +1,77 @@
+"""End-to-end milestone against real models: plan with the planner role,
+approve through the gate, then let the executor role actually create and test
+a file on disk.
+
+Gated on NISSE_LIVE_PLANNER_MODEL like the planning test — it needs a model
+that holds the tool-call contract on both ends.
+"""
+
+import io
+import os
+from pathlib import Path
+
+import pytest
+
+from nisse_dev.control import EXECUTING, Orchestrator
+from nisse_dev.envfile import load_env_file
+from nisse_dev.executor import LLMExecutor
+from nisse_dev.llm import LiteLLMClient, RoleMap
+from nisse_dev.oplog import OpLog
+from nisse_dev.planner import LLMPlanningAgent
+from nisse_dev.state import StateStore
+from nisse_dev.tools import Workspace
+from nisse_dev.transport import InMemoryTransport
+
+load_env_file(Path(__file__).resolve().parents[2] / ".env")
+
+SENTINEL = "NISSE_LIVE_PLANNER_MODEL"
+
+pytestmark = [
+    pytest.mark.integration,
+    pytest.mark.skipif(
+        not os.environ.get(SENTINEL),
+        reason=f"no live planner route configured ({SENTINEL} unset)",
+    ),
+]
+
+
+def test_plan_approve_execute_produces_a_real_file(tmp_path: Path) -> None:
+    assert os.environ.get("NISSE_LLM_TOKEN"), (
+        f"{SENTINEL} is set, so the live path is expected to work, "
+        "but NISSE_LLM_TOKEN is missing"
+    )
+    # Both roles use the capable model here: the point is the whole gated
+    # loop over a real proxy, not local-model competence (measured separately).
+    model = os.environ[SENTINEL]
+    roles = RoleMap(executor=model, planner=model, delegate=model, consultant=model)
+    client = LiteLLMClient.from_env()
+    store = StateStore(tmp_path / "state.db", oplog=OpLog("nisse-dev", io.StringIO()))
+    workspace = Workspace(tmp_path / "work", timeout_s=60)
+    transport = InMemoryTransport()
+    orchestrator = Orchestrator(
+        store,
+        transport,
+        LLMPlanningAgent(client, store, roles),
+        operators={"don"},
+        roles=roles,
+        executor=LLMExecutor(client, store, roles, workspace, max_turns=10),
+    )
+    orchestrator.start()
+
+    transport.receive(
+        "don",
+        "use greet. Milestone 1: create greet.py in the workspace root defining "
+        "greet(name) returning 'Hello, <name>!', and verify it by running python.",
+    )
+    transport.receive("don", "approve")  # architecture gate
+    transport.receive("don", "approve")  # milestone gate
+    transport.receive("don", "start milestone 1")
+
+    state = store.get_state()
+    assert state is not None
+    assert state.state in (EXECUTING, "AWAIT_INPUT")
+
+    created = list(workspace.root.rglob("*.py"))
+    assert created, f"executor created no Python file; said: {transport.outbound[-1]}"
+    combined = "\n".join(p.read_text() for p in created)
+    assert "def greet" in combined