VAlert closable prop and variant defaults change Vuetify 2 to Vuetify 3

A design goal is to use VAlert as the inline, persistent alert surface in a Vue 3 application with Vuetify 3 while keeping transient notification noise low. The intent is to reserve VSnackbar for transient notifications and keep VAlert for contextual, non-auto-dismissing feedback.

The context involves a configuration transition from Vuetify 2 to Vuetify 3. The alert API surface changed, including the rename of the dismissible prop to closable and changes to slot usage for dismiss behavior. Variant styling and CSS variable theming also changed across Vuetify 3 minor releases, affecting visual weight without code changes. Filled variants increase prominence and risk noise for non-critical messages.

With version-sensitive prop names and shifting defaults, a clear decision point remains on how to define quiet, useful alerts and maintain a boundary between VAlert and global snackbar usage.

Which variant and type combination is documented as the quiet default for non-critical inline feedback in the current Vuetify 3 VAlert? Does closable true preserve the same slot behavior as Vuetify 2 dismissible for custom close content? What policy signals separate VAlert usage from VSnackbar during a Vuetify 2 to Vuetify 3 migration?