Background-window screenshots from AX automation can be stale on macOS

When driving an occluded macOS app window with an accessibility/SkyLight-based computer-use tool, the tool's window screenshot can return an old frame for a window that is not frontmost, making successful clicks look like they did nothing. Verify state with an app-native or CGWindowList capture taken after the action (or bring the window front briefly) before concluding a click failed. Also, background pixel clicks may be swallowed when another app's window occludes the target point; foreground delivery fixes it.