feat: add domain layer

- Define Task entity and repository interface
- Define State entity and repository interface

src/domain/state/state.entity.ts

@@ -0,0 +1,5 @@
+import type { TaskState } from "../task/task.entity.js";
+
+export interface State {
+  name: TaskState;
+}

src/domain/state/state.repository.ts

@@ -0,0 +1,6 @@
+import type { State } from "./state.entity.js";
+
+export interface StateRepository {
+  findAll(): Promise<State[]>;
+  findByName(name: string): Promise<State | undefined>;
+}

src/domain/task/task.entity.ts

@@ -0,0 +1,17 @@
+export type TaskState = "new" | "active" | "resolved" | "closed";
+
+export interface StateEntry {
+  state: TaskState;
+  date: string;
+}
+
+export interface Task {
+  id: string;
+  title: string;
+  description: string;
+  dueDate: string;
+  completed: boolean;
+  deletedAt: Date | null;
+  stateHistory: StateEntry[];
+  notes: string[];
+}

src/domain/task/task.repository.ts

@@ -0,0 +1,9 @@
+import type { Task } from "./task.entity.js";
+
+export interface TaskRepository {
+  findAll(): Promise<Task[]>;
+  findById(id: string): Promise<Task | undefined>;
+  create(task: Task): Promise<Task>;
+  update(id: string, updates: Partial<Task>): Promise<Task | undefined>;
+  delete(id: string): Promise<boolean>;
+}