feat(cloud): surface cancellation over the internal Host<->Cloud protocol

- LeaseRenewalResponse gains cancel_requested (populated from the
  repository's renew_lease result)
- TerminalResultRequest.status widened to accept "cancelled"
- Add internal API tests for a renewal surfacing cancel_requested=True
  and a cancelled terminal report being accepted/idempotent

tests/test_host_agent_internal_api.py

@@ -473,10 +473,32 @@ def test_lease_renewal_extends_active_assignment(tmp_path) -> None:
 
     assert response.status_code == 200
     assert response.json()["status"] == "renewed"
+    assert response.json()["cancel_requested"] is False
     renewed_expiry = datetime.fromisoformat(response.json()["lease_expires_at"])
     assert renewed_expiry > original_time + timedelta(seconds=30)
 
 
+def test_lease_renewal_surfaces_pending_cancellation(tmp_path) -> None:
+    client, pool = _build_client(tmp_path)
+    _seed_active_assignment(pool)
+    pool.store.request_task_cancellation("active-task", requested_at=datetime.now(UTC))
+
+    response = client.post(
+        "/internal/v1/hosts/host-a/assignments/active-task/renew",
+        headers={"Authorization": "Bearer token-a"},
+        json={
+            "host_id": "host-a",
+            "task_id": "active-task",
+            "attempt": 1,
+            "lease_id": "active-lease",
+        },
+    )
+
+    assert response.status_code == 200
+    assert response.json()["status"] == "renewed"
+    assert response.json()["cancel_requested"] is True
+
+
 def test_stale_renewal_returns_typed_conflict(tmp_path) -> None:
     client, pool = _build_client(tmp_path)
     _seed_active_assignment(pool)
@@ -526,6 +548,37 @@ def test_terminal_result_is_idempotent_through_internal_api(tmp_path) -> None:
     assert pool.store.get_task("active-task").status == "done"  # type: ignore[union-attr]
 
 
+def test_cancelled_terminal_result_is_accepted_and_idempotent(tmp_path) -> None:
+    client, pool = _build_client(tmp_path)
+    _seed_active_assignment(pool)
+    pool.store.request_task_cancellation("active-task", requested_at=datetime.now(UTC))
+    payload = {
+        "host_id": "host-a",
+        "task_id": "active-task",
+        "attempt": 1,
+        "lease_id": "active-lease",
+        "status": "cancelled",
+        "failure_reason": "cancellation requested by control plane",
+    }
+
+    first = client.post(
+        "/internal/v1/hosts/host-a/assignments/active-task/result",
+        headers={"Authorization": "Bearer token-a"},
+        json=payload,
+    )
+    repeated = client.post(
+        "/internal/v1/hosts/host-a/assignments/active-task/result",
+        headers={"Authorization": "Bearer token-a"},
+        json=payload,
+    )
+
+    assert first.status_code == 200
+    assert first.json()["status"] == "recorded"
+    assert repeated.status_code == 200
+    assert repeated.json()["status"] == "already_recorded"
+    assert pool.store.get_task("active-task").status == "cancelled"  # type: ignore[union-attr]
+
+
 def test_conflicting_repeated_result_returns_stale_lease_conflict(tmp_path) -> None:
     client, pool = _build_client(tmp_path)
     _seed_active_assignment(pool)