cmd/k8s-operator,kube: set app name for Kubernetes Operator proxies (#13410)

Updates tailscale/corp#22920

Signed-off-by: Irbe Krumina <irbe@tailscale.com>

cmd/tailscaled/depaware.txt

@@ -279,7 +279,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    L    tailscale.com/ipn/store/awsstore                             from tailscale.com/ipn/store
    L    tailscale.com/ipn/store/kubestore                            from tailscale.com/ipn/store
         tailscale.com/ipn/store/mem                                  from tailscale.com/ipn/ipnlocal+
-   L    tailscale.com/kube                                           from tailscale.com/ipn/store/kubestore
+        tailscale.com/kube                                           from tailscale.com/ipn/store/kubestore+
         tailscale.com/licenses                                       from tailscale.com/client/web
         tailscale.com/log/filelogger                                 from tailscale.com/logpolicy
         tailscale.com/log/sockstatlog                                from tailscale.com/ipn/ipnlocal

cmd/tailscaled/tailscaled.go

@@ -417,6 +417,10 @@ func run() (err error) {
 
 	sys.Set(driveimpl.NewFileSystemForRemote(logf))
 
+	if app := envknob.App(); app != "" {
+		hostinfo.SetApp(app)
+	}
+
 	return startIPNServer(context.Background(), logf, pol.PublicID, sys)
 }