feat(m9): todo/kanban with DnD, assignee notify, completion, tests, e2e

- TodoRepository (column CRUD, item CRUD, soft-delete, ordering, maxOrderIndex,
  project isolation) + TodoService (lazy standard-column init, member/admin
  permission, create/update/move/toggleComplete/delete, todo_assigned notify,
  todo_created/updated/completed activity logs, SSE todo.updated)
- APIs: columns + items (GET/POST/PATCH/DELETE), toggleComplete + move
- KanbanBoard client (HTML5 drag&drop move, new task per column, complete),
  todos page, ProjectNav ToDo link
- Unit tests (TodoRepository, TodoService) + e2e todo-kanban

tests/e2e/todo-kanban.spec.ts

@@ -0,0 +1,79 @@
+import { test, expect } from '@playwright/test';
+
+function unique(prefix: string): string {
+  return `${prefix}-${Date.now()}-${Math.floor(Math.random() * 1_000_000)}`;
+}
+
+async function setupOwner(page: import('@playwright/test').Page) {
+  const email = unique('owner') + '@example.com';
+  await page.goto('/login');
+  await page.getByRole('button', { name: '新規登録はこちら' }).click();
+  await page.getByLabel('表示名').fill('Owner');
+  await page.getByLabel('メールアドレス').fill(email);
+  await page.getByLabel('パスワード').fill('password123');
+  await page.getByRole('button', { name: '登録する' }).click();
+  await expect(page).toHaveURL(/\/dashboard/);
+  await page.getByLabel('プロジェクト名').fill(unique('Proj'));
+  await page.getByRole('button', { name: '新規プロジェクト' }).click();
+  await expect(page).toHaveURL(/\/projects\/\d+$/);
+  return Number(page.url().match(/\/projects\/(\d+)/)![1]);
+}
+
+test.describe('todo / kanban', () => {
+  test('create a task, complete it, and move it to Done', async ({ page }) => {
+    const projectId = await setupOwner(page);
+
+    // 標準カラム取得
+    const colsRes = await page.request.get(
+      `/api/projects/${projectId}/todos/columns`
+    );
+    const cols = (
+      (await colsRes.json()) as { columns: { id: number; name: string }[] }
+    ).columns;
+    const backlog = cols.find((c) => c.name === 'Backlog')!;
+    const done = cols.find((c) => c.name === 'Done')!;
+
+    // タスク作成(API)
+    const title = unique('Task');
+    const createRes = await page.request.post(
+      `/api/projects/${projectId}/todos/items`,
+      {
+        data: {
+          title,
+          columnId: backlog.id,
+          priority: 'high',
+          dueDate: '2026-12-31',
+        },
+      }
+    );
+    expect(createRes.ok()).toBeTruthy();
+    const { item } = (await createRes.json()) as { item: { id: number } };
+
+    // ボードに表示される
+    await page.goto(`/projects/${projectId}/todos`);
+    await expect(page.getByTestId(`todo-card-${item.id}`)).toBeVisible();
+    await expect(page.getByText(title)).toBeVisible();
+
+    // 完了(API) → リロードで取り消し線が反映される
+    const completeRes = await page.request.patch(
+      `/api/projects/${projectId}/todos/items/${item.id}`,
+      { data: { toggleComplete: true } }
+    );
+    expect(completeRes.ok()).toBeTruthy();
+    await page.reload();
+    await expect(page.getByTestId(`todo-card-${item.id}`)).toHaveClass(
+      /line-through/
+    );
+
+    // Doneカラムへ移動(API)
+    const moveRes = await page.request.patch(
+      `/api/projects/${projectId}/todos/items/${item.id}`,
+      { data: { columnId: done.id, orderIndex: 0 } }
+    );
+    expect(moveRes.ok()).toBeTruthy();
+    await page.reload();
+    await expect(
+      page.getByTestId(`kanban-column-${done.id}`).getByText(title)
+    ).toBeVisible();
+  });
+});