refactor(types): move BackupRow and BackupsList out of route handler into src/types/backups.ts

Resolves the single component → route-handler import in the codebase
(`components/admin/backups-section.tsx ← app/api/admin/backups/route.ts`)
flagged by the v1.4.39 org audit (recommendation #2). The DTOs now live
in `src/types/backups.ts`; the route handler keeps owning the HTTP
contract and re-imports the shared types from there.

src/components/admin/backups-section.tsx

@@ -41,7 +41,7 @@ import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import { formatDateTime } from "@/lib/format";
 import { useFormatters, useTranslations } from "@/lib/i18n/context";
-import type { BackupRow, BackupsList } from "@/app/api/admin/backups/route";
+import type { BackupRow, BackupsList } from "@/types/backups";
 import { getApiErrorMessage } from "./_shared";
 
 /**