I decided against the second due to installation's fun name-shorthand logic making it so entering "plushu-example-plugin" would give the same result as "example-plugin", etc.
Still thinking about pluginifying runhook.
Kind of against it because I kind of want plushu to have less of dokku's constant plugins-re-entering-dokku-by-calling-dokku-commands behavior.
OTOH, having plugins reenter through "plushu" means less constructing-the-absolute-path stuff (and you're almost guaranteed it's going to happen at least once with plushu -c).
And the big problem with Dokku's re-entrant commands (every plugin is hard-wired to other plugins that expect a specific plugin by name) doesn't happen with hooks. (It is yet another double-spawning shell, though.)
Maybe that first level of plugin-handling (commands etc) should be handled via source? (And then the commands script gets some other name that means "file that always gets sourced" because, hey, we don't have to keep it for backcompat with dokku)
plushook (nee runhook) will not be made into a plugin. It is an inextricable, irreplaceable aspect of the Plushu core, equal to the main plushu script (see #15 (comment) for the full tirade).
Hookifying plugin installation, however, might happen: however, that is an issue for the (now separated) plushu/plushu-plugins-plugin.