First thing that I found is that filenames (Pwentropy.subs.php, Pwentropy.controller.php, Pwentropy.class.php) are starting from BIG letter, while in package-info.xml in hooks instructions they are lowercase, so hooks are not loaded.
Second:
In file Pwentropy.subs.php
'enabled' => !empty($modSettings['pwentropy_enabled']),
needs to be
'enabled' => true,
otherwise tab in menu will not be visible.
Also in file Pwentropy.subs.php in function imr_pwentropy() this code needs to be removed, because with it subaction with settings page does not work:
if (empty($modSettings['pwentropy_enabled']))
return;
//edit:
but there is still error when I'm typing password on registration page: