test(cli): isolate WebUI interrupt polling

nanobot/cli/webui_support.py

@@ -443,6 +443,7 @@ def _attach_to_background_gateway(
     runtime: "GatewayRuntime",
     *,
     poll_hook: Callable[[], None] | None = None,
+    sleep: Callable[[float], None] = time.sleep,
 ) -> None:
     """Keep a WebUI launcher attached without taking ownership of the gateway."""
     _print_webui_foreground_lifecycle(attached=True)
@@ -450,7 +451,7 @@ def _attach_to_background_gateway(
         while runtime.status().running:
             if poll_hook is not None:
                 poll_hook()
-            time.sleep(0.5)
+            sleep(0.5)
     except KeyboardInterrupt:
         console.print("\n[yellow]WebUI launcher detached.[/yellow]")
         return

tests/cli/test_commands.py

@@ -2565,7 +2565,7 @@ def test_webui_foreground_attaches_to_existing_managed_gateway(monkeypatch, tmp_
     assert seen["open_kwargs"] == {"wait": False}
 
 
-def test_attach_to_background_gateway_detaches_on_ctrl_c(monkeypatch, capsys) -> None:
+def test_attach_to_background_gateway_detaches_on_ctrl_c(capsys) -> None:
     stopped = False
 
     class _FakeRuntime:
@@ -2580,9 +2580,7 @@ def test_attach_to_background_gateway_detaches_on_ctrl_c(monkeypatch, capsys) ->
     def _interrupt(_seconds: float) -> None:
         raise KeyboardInterrupt
 
-    monkeypatch.setattr("nanobot.cli.webui_support.time.sleep", _interrupt)
-
-    cli_webui_support._attach_to_background_gateway(_FakeRuntime())
+    cli_webui_support._attach_to_background_gateway(_FakeRuntime(), sleep=_interrupt)
 
     assert stopped is False
     output = capsys.readouterr().out