feat(training-plans): 添加训练项目管理功能

- 新增训练项目模型、DTO和服务，支持创建、更新、删除和批量操作训练项目
- 在控制器中实现训练项目的相关API，包括添加、批量添加、获取、更新、删除和标记完成状态
- 提供训练项目的完成统计功能，支持获取训练计划下所有项目的完成情况
- 更新训练计划模块以集成训练项目管理功能

src/training-plans/models/schedule-exercise.model.ts

@@ -0,0 +1,74 @@
+import { Column, DataType, ForeignKey, Model, PrimaryKey, Table, BelongsTo } from 'sequelize-typescript';
+import { TrainingPlan } from './training-plan.model';
+
+export type ScheduleItemType = 'exercise' | 'rest' | 'note';
+
+@Table({
+  tableName: 't_schedule_exercises',
+  underscored: true,
+})
+export class ScheduleExercise extends Model {
+  @PrimaryKey
+  @Column({
+    type: DataType.UUID,
+    defaultValue: DataType.UUIDV4,
+  })
+  declare id: string;
+
+  @ForeignKey(() => TrainingPlan)
+  @Column({ type: DataType.STRING, allowNull: false })
+  declare trainingPlanId: string;
+
+  @BelongsTo(() => TrainingPlan)
+  declare trainingPlan: TrainingPlan;
+
+  @Column({ type: DataType.STRING, allowNull: false })
+  declare userId: string;
+
+  @Column({ type: DataType.STRING, allowNull: false, comment: '项目标识key' })
+  declare key: string;
+
+  @Column({ type: DataType.STRING, allowNull: false, comment: '项目名称' })
+  declare name: string;
+
+  @Column({ type: DataType.STRING, allowNull: true, comment: '项目分类' })
+  declare category: string;
+
+  @Column({ type: DataType.INTEGER, allowNull: true, comment: '组数' })
+  declare sets: number;
+
+  @Column({ type: DataType.INTEGER, allowNull: true, comment: '重复次数' })
+  declare reps: number;
+
+  @Column({ type: DataType.INTEGER, allowNull: true, comment: '持续时长(秒)' })
+  declare durationSec: number;
+
+  @Column({ type: DataType.INTEGER, allowNull: true, comment: '休息时长(秒)' })
+  declare restSec: number;
+
+  @Column({ type: DataType.TEXT, allowNull: true, comment: '备注' })
+  declare note: string;
+
+  @Column({
+    type: DataType.ENUM('exercise', 'rest', 'note'),
+    allowNull: false,
+    defaultValue: 'exercise',
+    comment: '项目类型'
+  })
+  declare itemType: ScheduleItemType;
+
+  @Column({ type: DataType.BOOLEAN, defaultValue: false, comment: '是否已完成' })
+  declare completed: boolean;
+
+  @Column({ type: DataType.INTEGER, allowNull: false, comment: '排序顺序' })
+  declare sortOrder: number;
+
+  @Column({ type: DataType.DATE, defaultValue: DataType.NOW })
+  declare createdAt: Date;
+
+  @Column({ type: DataType.DATE, defaultValue: DataType.NOW })
+  declare updatedAt: Date;
+
+  @Column({ type: DataType.BOOLEAN, defaultValue: false, comment: '是否已删除' })
+  declare deleted: boolean;
+}