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

lib/api/services.ts

@@ -14,6 +14,8 @@ import { ProjectNoteRepository } from '@/repositories/ProjectNoteRepository';
 import { ChatService } from '@/services/ChatService';
 import { ChatRepository } from '@/repositories/ChatRepository';
 import { getSseHub } from '@/lib/sse/hub';
+import { TodoService } from '@/services/TodoService';
+import { TodoRepository } from '@/repositories/TodoRepository';
 
 /**
  * Route Handler用に各Repository/Serviceを構築するファクトリ。
@@ -68,6 +70,17 @@ export function createChatService(): ChatService {
   );
 }
 
+export function createTodoService(): TodoService {
+  const db = getDb();
+  return new TodoService(
+    new TodoRepository(db),
+    new ProjectMemberRepository(db),
+    new NotificationService(new NotificationRepository(db)),
+    new ActivityLogService(new ActivityLogRepository(db)),
+    getSseHub()
+  );
+}
+
 export function createUserRepository(): UserRepository {
   return new UserRepository(getDb());
 }