fix: Service 层移除直接持有的 *gorm.DB，引入 Repository Transaction 方法

- ReactionStore/FollowStore/EnergyStore/FavoriteStore 接口新增 Transaction 方法
- EnergyStore.Transaction 支持跨仓库事务（EnergyStore + FundStore）
- ReactionRepo/FollowRepo/FavoriteRepo/EnergyRepo 实现 Transaction 方法
- ReactionRepo 新增 GetPostLikesCount 方法，消除 Service 直查 DB
- ReactionService/FollowService/FavoriteService/EnergyService 移除 db 字段
- EnergyRepo 通过 SetFundStore 注入 FundStore 用于跨仓库事务
- 更新 deps_extra.go 构造函数调用

internal/service/reaction_service.go

@@ -4,10 +4,7 @@ import (
 	"fmt"
 	"time"
 
-	"metazone.cc/metalab/internal/common"
 	"metazone.cc/metalab/internal/model"
-
-	"gorm.io/gorm"
 )
 
 // ReactionType 反应类型
@@ -21,13 +18,12 @@ const (
 
 // ReactionService 赞/踩业务逻辑
 type ReactionService struct {
-	db   *gorm.DB
 	repo ReactionStore
 }
 
 // NewReactionService 构造函数
-func NewReactionService(db *gorm.DB, repo ReactionStore) *ReactionService {
-	return &ReactionService{db: db, repo: repo}
+func NewReactionService(repo ReactionStore) *ReactionService {
+	return &ReactionService{repo: repo}
 }
 
 // ToggleLike 切换点赞（含踩互斥逻辑）
@@ -35,9 +31,7 @@ func NewReactionService(db *gorm.DB, repo ReactionStore) *ReactionService {
 func (s *ReactionService) ToggleLike(userID, postID uint) (bool, error) {
 	var isLiked bool
 
-	err := s.db.Transaction(func(tx *gorm.DB) error {
-		txRepo := s.repo.WithTx(tx)
-
+	err := s.repo.Transaction(func(txRepo ReactionStore) error {
 		// 查当前状态
 		_, likeErr := txRepo.FindLike(userID, postID)
 		hasLike := likeErr == nil
@@ -104,9 +98,7 @@ func (s *ReactionService) recordLikeForAggregation(postID uint, likerID uint) {
 func (s *ReactionService) ToggleDislike(userID, postID uint) (bool, error) {
 	var isDisliked bool
 
-	err := s.db.Transaction(func(tx *gorm.DB) error {
-		txRepo := s.repo.WithTx(tx)
-
+	err := s.repo.Transaction(func(txRepo ReactionStore) error {
 		// 查当前状态
 		_, likeErr := txRepo.FindLike(userID, postID)
 		hasLike := likeErr == nil
@@ -165,12 +157,9 @@ func (s *ReactionService) GetReaction(userID, postID uint) (ReactionType, error)
 
 // GetPostLikesCount 查询文章点赞数（公开展示）
 func (s *ReactionService) GetPostLikesCount(postID uint) (int, error) {
-	var post model.Post
-	if err := s.db.Select("likes_count").First(&post, postID).Error; err != nil {
-		if err == gorm.ErrRecordNotFound {
-			return 0, common.ErrPostNotFound
-		}
-		return 0, fmt.Errorf("查询文章失败: %w", err)
+	count, err := s.repo.GetPostLikesCount(postID)
+	if err != nil {
+		return 0, fmt.Errorf("查询文章点赞数: %w", err)
 	}
-	return post.LikesCount, nil
+	return count, nil
 }