Function focus_window 

pub fn focus_window(
    state: &Arc<AppState>,
    args: &Value,
) -> Result<Value, String>

Focus a specific window by label.

Uses the CEF Views Window::activate() API on all platforms (via post_focus_window → FocusWindowTask). On Windows in Views mode, browser.host().window_handle() returns NULL — the previous direct SetForegroundWindow path silently failed there. Views’ activate() resolves the actual top-level HWND through browser_view_get_for_browser → window() which is the only correct way to reach it in Views mode.