Design a task system with assignments

You are implementing an in-memory **task management system** (no database required). The system needs basic CRUD features and some ranking/sorting functionality. ### Part A — Core data model A **Task** can be assigned to **multiple people**. Model this using a separate **Assignment** concept. Design classes (or data structures) such that: - `Task` stores only **general metadata**, e.g. `taskId`, `title`, `description`, `createdAt`, `priority`, etc. - Each **Assignment** represents “this task assigned to this person” and stores assignment-specific fields: - `assigneeId` - `startTime` - `endTime` - any other assignment-specific info - A single task can have 0..N assignments. Explain: - What fields belong on `Task` vs `Assignment`, and why. - How you will link assignments to tasks (IDs, references). ### Part B — Operations (CRUD + ranking) Specify and implement (at least at the interface level) operations such as: - Create / read / update / delete tasks - Create / update / delete assignments - List tasks with a “ranking”/ordering requirement (e.g., sort by priority, due date, created time, or a composite key) Clarify: - What should happen when deleting a task that has assignments. - What your ranking key is and whether ties are stable. ### Part C — Production/refactor discussion If this were production code, how would you refactor the solution? Discuss layering (API/service/storage), validation, error handling, testability, and how you’d evolve the design when requirements change.