Custom template for a specific page within module for Drupal 7
I believe the original template name you had with the percent symbol was correct. The problem is you are doing it in a module, not in a theme.

By default, you have to put the template in your theme for it to be picked up automatically.

Also, in module info files, the use of files[] = something.ext is only for files that contain classes, so Drupal can autoload them. Files like template files, module files, installation files, etc. don't go in there.