feat(prepare-win): stream toolchain/WU output to the console live

pypsrp's execute_ps is fully blocking, so Install-CIToolchain / Windows
Update output only appeared at the end behind a "still running (Ns)"
heartbeat. Add WinRmTransport.run_streaming: drive the script via pypsrp's
incremental begin_invoke/poll_invoke, emitting output, Write-Host
(information) and error stream lines as they arrive over the same WinRM
channel.

_run_with_heartbeat now prefers run_streaming (suppressing the CI_EXITCODE
marker line) and falls back to the blocking heartbeat only on an unexpected
pypsrp error — TransportError still propagates so the 3010 reboot handling
is unaffected.

tests/python/test_winrm_transport.py

@@ -193,3 +193,89 @@ def test_is_ready_true_when_run_succeeds(monkeypatch: pytest.MonkeyPatch) -> Non
     _install_fake_pypsrp(monkeypatch, fake)
     t = WinRmTransport("10.0.0.1", "user", "pwd")
     assert t.is_ready() is True
+
+
+def _install_fake_streaming(monkeypatch: pytest.MonkeyPatch, *, with_error: bool = False) -> None:
+    """Inject fake pypsrp.powershell + complex_objects for run_streaming tests."""
+    class _State:
+        NOT_STARTED, RUNNING, COMPLETED, FAILED, STOPPED, STOPPING, DISCONNECTED = range(7)
+
+    class _Streams:
+        def __init__(self) -> None:
+            self.information: list[Any] = []
+            self.error: list[Any] = []
+
+    class _FakePS:
+        def __init__(self, _pool: Any) -> None:
+            self.state = _State.NOT_STARTED
+            self.output: list[Any] = []
+            self.streams = _Streams()
+            self._poll = 0
+
+        def add_script(self, script: str) -> None:
+            self.script = script
+
+        def begin_invoke(self) -> None:
+            self.state = _State.RUNNING
+
+        def poll_invoke(self, *_a: Any, **_k: Any) -> None:
+            self._poll += 1
+            if self._poll == 1:
+                self.output.append("line1")
+                self.streams.information.append(types.SimpleNamespace(message_data="hostmsg"))
+            elif self._poll == 2:
+                self.output.append("line2")
+                if with_error:
+                    self.streams.error.append("boom")
+                self.state = _State.COMPLETED
+
+        def end_invoke(self) -> None:
+            pass
+
+    class _FakePool:
+        def __init__(self, wsman: Any) -> None:
+            self.wsman = wsman
+
+        def open(self) -> None:
+            pass
+
+        def close(self) -> None:
+            pass
+
+    co = types.ModuleType("pypsrp.complex_objects")
+    co.PSInvocationState = _State  # type: ignore[attr-defined]
+    psmod = types.ModuleType("pypsrp.powershell")
+    psmod.PowerShell = _FakePS  # type: ignore[attr-defined]
+    psmod.RunspacePool = _FakePool  # type: ignore[attr-defined]
+    monkeypatch.setitem(sys.modules, "pypsrp.complex_objects", co)
+    monkeypatch.setitem(sys.modules, "pypsrp.powershell", psmod)
+    monkeypatch.setattr("ci_orchestrator.transport.winrm.time.sleep", lambda _s: None)
+
+
+def test_run_streaming_emits_lines(monkeypatch: pytest.MonkeyPatch) -> None:
+    fake = _FakeClient()
+    _install_fake_pypsrp(monkeypatch, fake)
+    _install_fake_streaming(monkeypatch)
+    t = WinRmTransport("10.0.0.1", "u", "p")
+    lines: list[str] = []
+    res = t.run_streaming("Write-Output 1", lines.append)
+    assert lines == ["line1", "hostmsg", "line2"]
+    assert res.ok and res.stdout == "line1\nline2"
+
+
+def test_run_streaming_raises_on_error(monkeypatch: pytest.MonkeyPatch) -> None:
+    fake = _FakeClient()
+    _install_fake_pypsrp(monkeypatch, fake)
+    _install_fake_streaming(monkeypatch, with_error=True)
+    t = WinRmTransport("10.0.0.1", "u", "p")
+    with pytest.raises(TransportCommandError):
+        t.run_streaming("x", lambda _s: None)
+
+
+def test_run_streaming_check_false(monkeypatch: pytest.MonkeyPatch) -> None:
+    fake = _FakeClient()
+    _install_fake_pypsrp(monkeypatch, fake)
+    _install_fake_streaming(monkeypatch, with_error=True)
+    t = WinRmTransport("10.0.0.1", "u", "p")
+    res = t.run_streaming("x", lambda _s: None, check=False)
+    assert not res.ok and "boom" in res.stderr