refactor: 移除workouts模块依赖，清理训练计划相关注释

src/ai-coach/ai-coach.module.ts

@@ -12,7 +12,6 @@ import { AiReportHistory } from './models/ai-report-history.model';
 import { UsersModule } from '../users/users.module';
 import { DietRecordsModule } from '../diet-records/diet-records.module';
 import { MedicationsModule } from '../medications/medications.module';
-import { WorkoutsModule } from '../workouts/workouts.module';
 import { MoodCheckinsModule } from '../mood-checkins/mood-checkins.module';
 import { WaterRecordsModule } from '../water-records/water-records.module';
 import { ChallengesModule } from '../challenges/challenges.module';
@@ -24,7 +23,6 @@ import { CosService } from '../users/cos.service';
     forwardRef(() => UsersModule),
     forwardRef(() => DietRecordsModule),
     forwardRef(() => MedicationsModule),
-    forwardRef(() => WorkoutsModule),
     forwardRef(() => MoodCheckinsModule),
     forwardRef(() => WaterRecordsModule),
     forwardRef(() => ChallengesModule),