refactor: 前后端目录结构模块化 + v2 优化移植与缺陷修复

前端:
- src/srv/api → src/api，按域分文件夹(auth/cluster/host/storage/deployment/collector)
- 新增 http.ts 引擎(http.get/post/put/delete)，域模块改用语义化调用
- index.html 增加 favicon(匹配应用 logo 的 emerald + Activity 脉冲)

后端分层增强(保留包名):
- 新增 repository/：从 models 拆出 JsonDB 持久化层(InitDB/GetDB/Shutdown/RequestSave)
- 新增 dto/：从 controllers 抽出各域请求契约(带 binding 校验)
- 新增 pkg/crypto、pkg/jwt：从 utils 拆出安全原语(外部 jwt 别名 jwtv5 避免冲突)
- models 只留领域实体 + sanitizer；utils 只留 gin/应用相关(response/errors)

v2 优化移植与缺陷修复:
- 移植密钥分离/SSH TOFU/并发写安全/Loki 生产级配置/Docker 加固
- 修复 deployment.go 并发丢更新、Helm values 重复键、EncryptField 哨兵、loki-gateway 端点等审计缺陷
- 实现真正的优雅关停(main.go http.Server + signal + repository.Shutdown)
- 修复登录契约:后端返回 accessToken，前端 auth.ts/Login.tsx 对齐
- 补 crypto/jwt/repository 单元测试(含并发写回归)

验证: go build/vet/test 全绿；npm run build 通过；登录→鉴权→优雅关停冒烟通过

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

backend/utils/response.go

@@ -20,18 +20,26 @@ type PageData struct {
 	PageSize int         `json:"pageSize"`
 }
 
+// Success 返回200状态码的成功响应
 func Success(c *gin.Context, data interface{}) {
 	c.JSON(http.StatusOK, Response{Code: 0, Message: "success", Data: data})
 }
 
+// Error 返回指定HTTP状态码的错误响应，status code与业务code一致
 func Error(c *gin.Context, code int, message string) {
-	c.JSON(http.StatusOK, Response{Code: code, Message: message})
+	httpStatus := code
+	if httpStatus < 100 || httpStatus >= 600 {
+		httpStatus = http.StatusBadRequest
+	}
+	c.JSON(httpStatus, Response{Code: code, Message: message})
 }
 
+// BadRequest 返回400状态码
 func BadRequest(c *gin.Context, message string) {
-	Error(c, 400, message)
+	c.JSON(http.StatusBadRequest, Response{Code: 400, Message: message})
 }
 
+// Unauthorized 返回401状态码
 func Unauthorized(c *gin.Context, message string) {
 	if message == "" {
 		message = "未登录或登录已过期"
@@ -39,6 +47,7 @@ func Unauthorized(c *gin.Context, message string) {
 	c.JSON(http.StatusUnauthorized, Response{Code: 401, Message: message})
 }
 
+// Forbidden 返回403状态码
 func Forbidden(c *gin.Context, message string) {
 	if message == "" {
 		message = "没有操作权限"
@@ -46,11 +55,28 @@ func Forbidden(c *gin.Context, message string) {
 	c.JSON(http.StatusForbidden, Response{Code: 403, Message: message})
 }
 
+// NotFound 返回404状态码
 func NotFound(c *gin.Context, message string) {
 	if message == "" {
 		message = "资源不存在"
 	}
-	Error(c, 404, message)
+	c.JSON(http.StatusNotFound, Response{Code: 404, Message: message})
+}
+
+// InternalServerError 返回500状态码
+func InternalServerError(c *gin.Context, message string) {
+	if message == "" {
+		message = "服务器内部错误"
+	}
+	c.JSON(http.StatusInternalServerError, Response{Code: 500, Message: message})
+}
+
+// ValidationError 返回422状态码（参数校验失败）
+func ValidationError(c *gin.Context, message string) {
+	if message == "" {
+		message = "参数校验失败"
+	}
+	c.JSON(http.StatusUnprocessableEntity, Response{Code: 422, Message: message})
 }
 
 func Pagination(c *gin.Context) (page, pageSize int) {
@@ -74,7 +100,7 @@ func IntParam(c *gin.Context, key string) (int, error) {
 
 func BindAndValidate(c *gin.Context, obj interface{}) bool {
 	if err := c.ShouldBindJSON(obj); err != nil {
-		BadRequest(c, "请求参数无效: "+err.Error())
+		ValidationError(c, "请求参数无效: "+err.Error())
 		return false
 	}
 	return true