feat: 新增心情打卡功能模块

实现心情打卡的完整功能，包括数据库表设计、API接口、业务逻辑和文档说明。支持记录多种心情类型、强度评分和统计分析功能。

src/mood-checkins/mood-checkins.module.ts

@@ -0,0 +1,15 @@
+import { Module } from '@nestjs/common';
+import { SequelizeModule } from '@nestjs/sequelize';
+import { MoodCheckinsService } from './mood-checkins.service';
+import { MoodCheckinsController } from './mood-checkins.controller';
+import { MoodCheckin } from './models/mood-checkin.model';
+import { UsersModule } from '../users/users.module';
+import { ActivityLogsModule } from '../activity-logs/activity-logs.module';
+
+@Module({
+  imports: [SequelizeModule.forFeature([MoodCheckin]), UsersModule, ActivityLogsModule],
+  providers: [MoodCheckinsService],
+  controllers: [MoodCheckinsController],
+  exports: [MoodCheckinsService],
+})
+export class MoodCheckinsModule { }