refactor: Skill状态字段从int改为string类型

- model/skill.go: Status字段从 int 改为 string，支持 "active"/"inactive"
- handler/skill_handler.go: 适配Status字段的类型变化，处理"1"/"0"和"active"/"inactive"两种格式
- repository/skill_repo.go: 更新Status字段的空值判断逻辑
- service/skill_service.go: 同步更新

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/internal/handler/skill_handler.go

@@ -245,7 +245,7 @@ func (h *SkillHandler) Create(c *gin.Context) {
 		SkillType: skillType,
 		SkillDesc: skillDesc,
 		Path:      filepath.Join(skillPath, "SKILL.md"),
-		Status:    1,
+		Status:    "active",
 	}
 
 	// 记录创建者
@@ -386,7 +386,7 @@ func (h *SkillHandler) Update(c *gin.Context) {
 	skillName := req.SkillName
 	skillDesc := req.SkillDesc
 	skillType := req.SkillType
-	var status int
+	var status string
 
 	if skillName == "" {
 		skillName = existingSkill.SkillName
@@ -397,15 +397,15 @@ func (h *SkillHandler) Update(c *gin.Context) {
 	if skillType == "" {
 		skillType = existingSkill.SkillType
 	}
-	// 处理 status：如果是空字符串则使用现有值，否则转换为整数
+	// 处理 status：如果是空字符串则使用现有值，否则使用传入的值
 	if req.Status == "" {
 		status = existingSkill.Status
 	} else {
 		// 支持传入数字或字符串
 		if req.Status == "1" || req.Status == "active" {
-			status = 1
+			status = "active"
 		} else if req.Status == "0" || req.Status == "inactive" {
-			status = 0
+			status = "inactive"
 		} else {
 			status = existingSkill.Status
 		}