Rename Assignments to Judge Assignments for clarity

Updates labels in admin round pages:
- "Assignments" → "Judge Assignments"
- "Manage Assignments" → "Manage Judge Assignments"
- "Current Assignments" → "Current Judge Assignments"
- Updated descriptions to reference judges instead of jury members

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/(admin)/admin/rounds/page.tsx

@@ -458,7 +458,7 @@ function SortableRoundRow({
             <DropdownMenuItem asChild>
               <Link href={`/admin/rounds/${round.id}/assignments`}>
                 <Users className="mr-2 h-4 w-4" />
-                Manage Assignments
+                Manage Judge Assignments
               </Link>
             </DropdownMenuItem>
             <DropdownMenuSeparator />