feat: show error when image preview fails

[sxyazi]

Before this change, when ya.image_info() and ya.image_show() failed, there was no way to determine the reason for the failure.

With this PR, a new second return value has been added to them, in the event of a failure, it will carry an Error userdata that provides the caller with the error message.

All built-in image previewers in Yazi have been updated to support this, that is, when an image preview fails, the error will be displayed in the preview pane so that the user knows what went wrong.

Deprecated API

ya.preview_widgets() has been deprecated and replaced by the new ya.preview_widget():

- ya.preview_widgets(job, { ui.Text("..."):area(job.area) })
+ ya.preview_widget(job, { ui.Text("..."):area(job.area) })

In addition to supporting the table parameter as the original ya.preview_widgets() did, the new ya.preview_widget() can also accept a single renderable element directly without the need to wrap it in a table:

- ya.preview_widgets(job, { ui.Text("..."):area(job.area) })
+ ya.preview_widget(job, ui.Text("..."):area(job.area))

Considering that ya.preview_widgets() has been widely used in previewers, it will continue to be available for a long time. Deprecation warnings will be added later, and it will eventually be removed.