Send a context from a panel page to a view integrated in it?
First thing to do is fix your view. In order to have author ID as a filter you need to add the "Content: Author" relationship. After adding that you will see a lot more options for User in the fields and filters. You can now chose "User: UID" for your contextual filter.

Next thing to do is to edit your panel. Add a user context to your panel and chose "Select a user" for the context type. Type in the username of the user and check "Reset identifier to username."

Now go to your panels content and edit the view settings. You should see the "User: UID" context at the top. Choose the "User ID" from the drop down.

You should now only see content from the user you chose in the context when viewing that panel page.