Yes, you can change the text orientation in the header. Use the header parameter of the columns property and set its vertical attribute value to true:
<script>
import { Grid } from "wx-svelte-grid";
import { getData } from "./common/data";
const { data } = getData();
const columns = [
header: {
text: "Company",
vertical: true,
},
footer: "Company",
},
];
</script>
<Grid {data} {columns} />