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/controllers/collector.go

@@ -1,6 +1,7 @@
 package controllers
 
 import (
+	"lokideploy/dto"
 	"lokideploy/models"
 	"lokideploy/services"
 	"lokideploy/utils"
@@ -16,20 +17,8 @@ func NewCollectorController() *CollectorController {
 	return &CollectorController{service: services.NewCollectorService()}
 }
 
-type CreateCollectorRequest struct {
-	Name             string `json:"name" binding:"required"`
-	Type             string `json:"type" binding:"required"`
-	LokiDeploymentID uint   `json:"lokiDeploymentID" binding:"required"`
-	HostID           *uint  `json:"hostID"`
-	ClusterID        *uint  `json:"clusterID"`
-	TargetDeployment string `json:"targetDeployment"`
-	Namespace        string `json:"namespace"`
-	LogPath          string `json:"logPath"`
-	Labels           string `json:"labels"`
-}
-
 func (ctrl *CollectorController) Create(c *gin.Context) {
-	var req CreateCollectorRequest
+	var req dto.CreateCollectorRequest
 	if !utils.BindAndValidate(c, &req) {
 		return
 	}