feat: add kanban board

src/kanban/buildKanbanBoard.test.ts

@@ -0,0 +1,86 @@
+import { describe, expect, it } from "vitest";
+import { Task } from "@/model/task";
+import { buildKanbanBoard } from "./buildKanbanBoard";
+
+function task(partial: Partial<Task> & Pick<Task, "id" | "title">): Task {
+	return {
+		description: "",
+		status: "todo",
+		priority: "medium",
+		tags: [],
+		assignee: "",
+		created: "2026-01-01T00:00:00.000Z",
+		updated: "2026-01-01T00:00:00.000Z",
+		...partial,
+	};
+}
+
+describe("buildKanbanBoard", () => {
+	const tasks: Task[] = [
+		task({
+			id: "a",
+			title: "Done one",
+			status: "done",
+			updated: "2026-01-01T00:00:02.000Z",
+		}),
+		task({
+			id: "b",
+			title: "Todo older",
+			status: "todo",
+			updated: "2026-01-01T00:00:01.000Z",
+		}),
+		task({
+			id: "c",
+			title: "Todo newer",
+			status: "todo",
+			updated: "2026-01-01T00:00:03.000Z",
+		}),
+		task({
+			id: "d",
+			title: "In progress",
+			status: "in-progress",
+			updated: "2026-01-01T00:00:04.000Z",
+		}),
+	];
+
+	it("returns all status columns in fixed order, including empty", () => {
+		const board = buildKanbanBoard(tasks);
+
+		expect(board.columns.map((col) => col.status)).toEqual([
+			"todo",
+			"in-progress",
+			"done",
+			"cancelled",
+		]);
+		expect(board.columns.map((col) => col.label)).toEqual([
+			"To Do",
+			"In Progress",
+			"Done",
+			"Cancelled",
+		]);
+		expect(board.columns[3].tasks).toEqual([]);
+	});
+
+	it("places each task into the column matching its status", () => {
+		const board = buildKanbanBoard(tasks);
+
+		expect(board.columns[0].tasks.map((t) => t.id)).toEqual(["c", "b"]);
+		expect(board.columns[1].tasks.map((t) => t.id)).toEqual(["d"]);
+		expect(board.columns[2].tasks.map((t) => t.id)).toEqual(["a"]);
+	});
+
+	it("sorts tasks within a column by updated desc", () => {
+		const board = buildKanbanBoard(tasks);
+		const todo = board.columns.find((col) => col.status === "todo");
+		expect(todo?.tasks.map((t) => t.id)).toEqual(["c", "b"]);
+	});
+
+	it("returns empty columns when there are no tasks", () => {
+		const board = buildKanbanBoard([]);
+
+		expect(board.columns).toHaveLength(4);
+		for (const col of board.columns) {
+			expect(col.tasks).toEqual([]);
+		}
+	});
+});