Entity struct for per-action lifecycle hooks (row + bulk).
Stores a hook function attached to one or more action names.
Used by entries like before_row_action, after_row_action,
on_row_action_success, on_row_action_error, and the bulk variants.
See MishkaGervaz.Table.Dsl.Hooks,
MishkaGervaz.Table.Entities.RowAction,
MishkaGervaz.Table.Entities.BulkAction, and
MishkaGervaz.Table.Web.Events.HookRunner.