tailcfg: add CapabilityOwner (#16426)

We would like to start sending whether a node is a Tailnet owner in netmap responses so that clients can determine what information to display to a user who wants to request account deletion.

Updates tailscale/corp#30016

Signed-off-by: kari-ts <kari@tailscale.com>

ipn/ipnlocal/local_test.go

@@ -826,10 +826,21 @@ func TestStatusPeerCapabilities(t *testing.T) {
 						tailcfg.CapabilityAdmin: {`{"test": "true}`},
 					}),
 				}).View(),
+				(&tailcfg.Node{
+					ID:           3,
+					StableID:     "baz",
+					Key:          makeNodeKeyFromID(3),
+					Hostinfo:     (&tailcfg.Hostinfo{}).View(),
+					Capabilities: []tailcfg.NodeCapability{tailcfg.CapabilityOwner},
+					CapMap: (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
+						tailcfg.CapabilityOwner: nil,
+					}),
+				}).View(),
 			},
 			expectedPeerCapabilities: map[tailcfg.StableNodeID][]tailcfg.NodeCapability{
 				tailcfg.StableNodeID("foo"): {tailcfg.CapabilitySSH},
 				tailcfg.StableNodeID("bar"): {tailcfg.CapabilityAdmin},
+				tailcfg.StableNodeID("baz"): {tailcfg.CapabilityOwner},
 			},
 			expectedPeerCapMap: map[tailcfg.StableNodeID]tailcfg.NodeCapMap{
 				tailcfg.StableNodeID("foo"): (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
@@ -838,6 +849,9 @@ func TestStatusPeerCapabilities(t *testing.T) {
 				tailcfg.StableNodeID("bar"): (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
 					tailcfg.CapabilityAdmin: {`{"test": "true}`},
 				}),
+				tailcfg.StableNodeID("baz"): (tailcfg.NodeCapMap)(map[tailcfg.NodeCapability][]tailcfg.RawMessage{
+					tailcfg.CapabilityOwner: nil,
+				}),
 			},
 		},
 		{

tailcfg/tailcfg.go

@@ -2367,6 +2367,7 @@ type NodeCapability string
 const (
 	CapabilityFileSharing        NodeCapability = "https://tailscale.com/cap/file-sharing"
 	CapabilityAdmin              NodeCapability = "https://tailscale.com/cap/is-admin"
+	CapabilityOwner              NodeCapability = "https://tailscale.com/cap/is-owner"
 	CapabilitySSH                NodeCapability = "https://tailscale.com/cap/ssh"                   // feature enabled/available
 	CapabilitySSHRuleIn          NodeCapability = "https://tailscale.com/cap/ssh-rule-in"           // some SSH rule reach this node
 	CapabilityDataPlaneAuditLogs NodeCapability = "https://tailscale.com/cap/data-plane-audit-logs" // feature enabled