refactor(model): 重构数据模型结构

- 将 Word 和 MemoryRecord 结构体拆分为独立文件
- 创建 request 包用于存放请求结构体
- 创建 response 包用于存放响应结构体
- 将 YoudaoResponse 移至独立模型文件
- 更新服务层接口参数类型为新的请求响应结构体
- 修改处理器层导入路径以使用新包结构

memora-api/internal/service/word.go

@@ -15,6 +15,8 @@ import (
 
 	"memora-api/internal/config"
 	"memora-api/internal/model"
+	"memora-api/internal/request"
+	"memora-api/internal/response"
 
 	"gorm.io/gorm"
 )
@@ -359,7 +361,7 @@ func containsAny(def string, ans string) bool {
 }
 
 // 提交复习答案
-func (s *WordService) SubmitReviewAnswer(req model.ReviewAnswerRequest) (*model.ReviewResult, error) {
+func (s *WordService) SubmitReviewAnswer(req request.ReviewAnswerRequest) (*response.ReviewResult, error) {
 	var record model.MemoryRecord
 	if err := s.db.Preload("Word").Where("id = ?", req.RecordID).First(&record).Error; err != nil {
 		return nil, err
@@ -387,7 +389,7 @@ func (s *WordService) SubmitReviewAnswer(req model.ReviewAnswerRequest) (*model.
 	// 更新记忆记录
 	s.updateMemoryRecord(record.WordID, correct)
 
-	return &model.ReviewResult{
+	return &response.ReviewResult{
 		Word:       word,
 		Correct:    correct,
 		Answer:     req.Answer,
@@ -422,9 +424,9 @@ func (s *WordService) GetStatistics() (map[string]interface{}, error) {
 	s.db.Model(&model.MemoryRecord{}).Where("last_reviewed_at >= ?", time.Now().Format("2006-01-02")).Count(&todayReviewed)
 
 	return map[string]interface{}{
-		"total_words":      totalWords,
-		"mastered_words":   masteredWords,
-		"need_review":      needReview,
-		"today_reviewed":   todayReviewed,
+		"total_words":    totalWords,
+		"mastered_words": masteredWords,
+		"need_review":    needReview,
+		"today_reviewed": todayReviewed,
 	}, nil
 }