feat(auth): make upload review a separate grant instead of an admin privilege

Reviewing the upload queue is now a per-user flag (reviews_uploads), not part
of the admin role: several people can hold it, a moderator can have it, and an
admin may not. Only admins grant or revoke it; existing admins keep it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/app/router.tsx

@@ -226,7 +226,9 @@ const myUploadsRoute = createRoute({ getParentRoute: () => appRoute, path: '/upl
 const uploadQueueRoute = createRoute({
   getParentRoute: () => appRoute,
   path: '/admin/uploads',
-  beforeLoad: adminOnly,
+  beforeLoad: ({ context }) => {
+    if (!context.user.reviews_uploads) throw redirect({ to: '/' });
+  },
   component: UploadQueuePage,
 });