refactor: move from union type to object enum

src/dashboard/buildDashboardView.ts

@@ -1,6 +1,7 @@
 import { Task } from "@/model/task";
 import { filterTasks, type TaskFilter } from "./filterTasks";
-import { groupTasks, type GroupBy, type TaskGroup } from "./groupTasks";
+import { GroupBy } from "./groupBy";
+import { groupTasks, type TaskGroup } from "./groupTasks";
 
 export type DashboardViewOptions = {
 	filter?: TaskFilter;
@@ -19,7 +20,7 @@ export function buildDashboardView(
 	options: DashboardViewOptions = {},
 ): DashboardView {
 	const filter = options.filter ?? {};
-	const groupBy = options.groupBy ?? "none";
+	const groupBy = options.groupBy ?? GroupBy.NONE;
 
 	const visibleTasks = filterTasks(tasks, filter);
 	const groups = groupTasks(visibleTasks, groupBy);