Registers every mishka_blog dashboard widget's own settings with the Settings page through the settings:register mishka_installer hook — so "Posts to show" is documented under the Blog tab (category: "blog", group Dashboard widgets) alongside the rest of the blog's settings, instead of hiding inside the dashboard's per-user layout where nothing else could see it.

It walks MishkaBlog.Application.dashboard_widgets/0 and asks each descriptor for its definitions (MishkaCmsCore.Dashboard.Widget.settings_definitions/1), which derives the key from Widget.setting_key/2 — the same function the dashboard reads through. A widget that adds a setting is registered by declaring it; there is no second list to keep in step, and a widget that declares none contributes nothing.

Every definition is scope: :user: the value belongs to the admin reading the board, and both editors — the card's gear and this tab — write the same Settings.put_user/3 row, so nobody ever sees anybody else's number. Registered in MishkaBlog.Application.

See MishkaBlog.Notifiers.NotifySettings for the sibling that registers the blog's notification toggles, and MishkaCmsCore.Settings.define/3.