Report which sources have a newer file instead of a single flag, and
show a Material badge at the top-end corner of each such dictionary's
icon. The section icon carries the badge while the section is
collapsed.
Compose compiler reports showed DownloadState's sealed root as Uncertain
and DownloadProgressState/SettingsUiState as runtime stability, so
skippability checks were deferred to runtime. The annotations make them
compile-time stable and turn any future mutable field into an explicit
contract break.