selectedSessionsSkippedActive is required in Translations, but only en.ts
had it. Every locale typed `: Translations` failed tsc -b with TS2741, which
breaks scripts/build/web.mjs. Add a translation next to
selectedSessionsDeleted in each of them (ar.ts goes through defineLocale and
falls back to English).
useToast holds one toast and only supports success|error, so the skipped
toast replaced the success toast in the same tick and the deleted count was
lost. Show a single toast instead: success with the count when nothing was
skipped, otherwise one error toast that carries both counts. Also drop the
duplicated comment.
e78e7ccdeb