feat(frontend): add Helm chart browser, monitoring, chart-references and values templates pages

Add new frontend pages for the multi-tenant OCDP platform:

- Charts page (/charts): Browse Harbor OCI registries to list Helm chart repositories
  and versions, with deploy modal to launch charts on selected clusters
- Monitoring page (/monitoring): Display cluster metrics (CPU/Memory/GPU usage)
  and per-node details with resource utilization bars
- Chart References page (/chart-references): CRUD for chart metadata references
- Values Templates page (/templates): CRUD for Helm values templates with version
  history and rollback support
- Sidebar: Add Charts navigation, update Storage and Templates links
- api.ts: Add all API client functions (clusterApi, registryApi, instanceApi,
  monitoringApi, storageApi, chartReferenceApi, valuesTemplateApi,
  workspaceApi, userApi) with full TypeScript types

Note: deploy flow and values template rollback not yet end-to-end tested.

backend/internal/domain/entity/audit_log.go

@@ -0,0 +1,90 @@
+package entity
+
+import (
+	"encoding/json"
+	"time"
+)
+
+// AuditAction 审计操作类型
+type AuditAction string
+
+const (
+	AuditActionCreate   AuditAction = "create"
+	AuditActionUpdate   AuditAction = "update"
+	AuditActionDelete   AuditAction = "delete"
+	AuditActionDeploy   AuditAction = "deploy"
+	AuditActionScale    AuditAction = "scale"
+	AuditActionLogin    AuditAction = "login"
+	AuditActionLogout   AuditAction = "logout"
+	AuditActionChangePassword AuditAction = "change_password"
+)
+
+// AuditResourceType 审计资源类型
+type AuditResourceType string
+
+const (
+	AuditResourceUser      AuditResourceType = "user"
+	AuditResourceWorkspace AuditResourceType = "workspace"
+	AuditResourceQuota     AuditResourceType = "quota"
+	AuditResourceCluster   AuditResourceType = "cluster"
+	AuditResourceRegistry  AuditResourceType = "registry"
+	AuditResourceInstance  AuditResourceType = "instance"
+	AuditResourceStorage   AuditResourceType = "storage"
+	AuditResourceTemplate  AuditResourceType = "template"
+)
+
+// AuditLog 审计日志实体
+type AuditLog struct {
+	ID           string
+	WorkspaceID  string
+	UserID       string
+	Action       AuditAction
+	ResourceType AuditResourceType
+	ResourceID   string
+	ResourceName string
+	Details      map[string]interface{}
+	IPAddress    string
+	UserAgent    string
+	CreatedAt    time.Time
+}
+
+// NewAuditLog 创建新审计日志
+func NewAuditLog(workspaceID, userID string, action AuditAction, resourceType AuditResourceType) *AuditLog {
+	now := time.Now()
+	return &AuditLog{
+		WorkspaceID:  workspaceID,
+		UserID:       userID,
+		Action:       action,
+		ResourceType: resourceType,
+		CreatedAt:    now,
+	}
+}
+
+// SetResource 设置关联资源
+func (a *AuditLog) SetResource(resourceID, resourceName string) {
+	a.ResourceID = resourceID
+	a.ResourceName = resourceName
+}
+
+// SetDetails 设置详细信息
+func (a *AuditLog) SetDetails(details map[string]interface{}) {
+	a.Details = details
+}
+
+// SetClientInfo 设置客户端信息
+func (a *AuditLog) SetClientInfo(ipAddress, userAgent string) {
+	a.IPAddress = ipAddress
+	a.UserAgent = userAgent
+}
+
+// DetailsJSON 将详情转为 JSON 字符串
+func (a *AuditLog) DetailsJSON() (string, error) {
+	if a.Details == nil {
+		return "{}", nil
+	}
+	data, err := json.Marshal(a.Details)
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}