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/services/collector.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"lokideploy/models"
+	"lokideploy/repository"
 	"lokideploy/utils"
 )
 
@@ -29,7 +30,7 @@ type CreateCollectorRequest struct {
 
 // fillAssociations 填充关联的 Loki / Host / Cluster（用于配置生成与展示）
 func (s *CollectorService) fillAssociations(c *models.Collector) {
-	db := models.GetDB()
+	db := repository.GetDB()
 	db.RLock()
 	defer db.RUnlock()
 	for i := range db.Deployments {
@@ -107,7 +108,7 @@ func (s *CollectorService) Create(req *CreateCollectorRequest) (*models.Collecto
 	}
 
 	collector := models.Collector{
-		ID:               models.GetDB().NextID("collectors"),
+		ID:               repository.GetDB().NextID("collectors"),
 		Name:             req.Name,
 		Type:             req.Type,
 		LokiDeploymentID: req.LokiDeploymentID,
@@ -129,18 +130,18 @@ func (s *CollectorService) Create(req *CreateCollectorRequest) (*models.Collecto
 	}
 	collector.Config = s.generateConfigSnapshot(&collector)
 
-	db := models.GetDB()
+	db := repository.GetDB()
 	db.Lock()
 	db.Collectors = append(db.Collectors, collector)
 	db.Unlock()
-	go db.Save()
+	db.RequestSave()
 
 	go s.Install(collector.ID)
 	return &collector, nil
 }
 
 func (s *CollectorService) Get(id uint) (*models.Collector, error) {
-	db := models.GetDB()
+	db := repository.GetDB()
 	db.RLock()
 	var found *models.Collector
 	for i := range db.Collectors {
@@ -159,7 +160,7 @@ func (s *CollectorService) Get(id uint) (*models.Collector, error) {
 }
 
 func (s *CollectorService) List(page, pageSize int) ([]models.Collector, int64, error) {
-	db := models.GetDB()
+	db := repository.GetDB()
 	db.RLock()
 	total := int64(len(db.Collectors))
 	start := (page - 1) * pageSize
@@ -181,7 +182,7 @@ func (s *CollectorService) List(page, pageSize int) ([]models.Collector, int64,
 }
 
 func (s *CollectorService) Update(id uint, updates map[string]interface{}) error {
-	db := models.GetDB()
+	db := repository.GetDB()
 	db.Lock()
 	defer db.Unlock()
 	for i := range db.Collectors {
@@ -202,7 +203,7 @@ func (s *CollectorService) Update(id uint, updates map[string]interface{}) error
 				db.Collectors[i].Labels = v
 			}
 			db.Collectors[i].UpdatedAt = time.Now()
-			go db.Save()
+			db.RequestSave()
 			return nil
 		}
 	}
@@ -214,7 +215,7 @@ func (s *CollectorService) Delete(id uint) error {
 	if err != nil {
 		return utils.ErrNotFound
 	}
-	db := models.GetDB()
+	db := repository.GetDB()
 	db.Lock()
 	for i, c := range db.Collectors {
 		if c.ID == id {
@@ -223,7 +224,7 @@ func (s *CollectorService) Delete(id uint) error {
 		}
 	}
 	db.Unlock()
-	go db.Save()
+	db.RequestSave()
 	// 异步卸载（用拷贝的 collector，避免删除后取不到）
 	go func() {
 		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)