How to create a panel for a argument path
I'm not sure what you are after. You just want the URL to look right, then all you need is Pathauto.

What you are asking however, is essentially how to tell Page manager to load content based on the title of the content. That could make sense, if it wasn't because you already load it by the ID, so loading it again would just be redundant.

If that's really what you want though, here goes:

Page manager doesn't know how to load nodes by title, so you will need to explain to it.

This is a called a Context.

See What are Ctools plugin (content type, access, etc), and how does one create them? for the basics of how to implement a ctools plugin. Look at the existing contexts in the ctools examples directory, and creating the context shouldn't be to hard.