opt: 优化数据库连接池，配置管理，错误处理

db/repo/resource_repository.go

@@ -68,38 +68,21 @@ func (r *ResourceRepositoryImpl) FindWithRelations() ([]entity.Resource, error)
 
 // FindWithRelationsPaginated 分页查找包含关联关系的资源
 func (r *ResourceRepositoryImpl) FindWithRelationsPaginated(page, limit int) ([]entity.Resource, int64, error) {
-	var resources []entity.Resource
-	var total int64
-
-	offset := (page - 1) * limit
-
-	// 优化查询：只预加载必要的关联，并添加排序
-	db := r.db.Model(&entity.Resource{}).
-		Preload("Category").
-		Preload("Pan").
-		Order("updated_at DESC") // 按更新时间倒序，显示最新内容
-
-	// 获取总数（使用缓存键）
-	cacheKey := fmt.Sprintf("resources_total_%d_%d", page, limit)
-	if cached, exists := r.cache[cacheKey]; exists {
-		if totalCached, ok := cached.(int64); ok {
-			total = totalCached
-		}
-	} else {
-		if err := db.Count(&total).Error; err != nil {
-			return nil, 0, err
-		}
-		// 缓存总数（5分钟）
-		r.cache[cacheKey] = total
-		go func() {
-			time.Sleep(5 * time.Minute)
-			delete(r.cache, cacheKey)
-		}()
+	// 使用新的分页查询功能
+	options := &PaginationOptions{
+		Page:     page,
+		PageSize: limit,
+		OrderBy:  "updated_at",
+		OrderDir: "desc",
+		Preloads: []string{"Category", "Pan"},
 	}
 
-	// 获取分页数据
-	err := db.Offset(offset).Limit(limit).Find(&resources).Error
-	return resources, total, err
+	result, err := PaginatedQuery[entity.Resource](r.db, options)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	return result.Data, result.Total, nil
 }
 
 // FindByCategoryID 根据分类ID查找