tailcfg,etc: remove unused tailcfg.Node.KeepAlive field

The server hasn't sent it in ages.

Updates #cleanup

Change-Id: I9695ab0f074ec6fb006e11faf3cdfc5ca049fbf8
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

tailcfg/tailcfg.go

@@ -242,8 +242,6 @@ type Node struct {
 	// current node doesn't have permission to know.
 	Online *bool `json:",omitempty"`
 
-	KeepAlive bool `json:",omitempty"` // open and keep open a connection to this peer
-
 	MachineAuthorized bool `json:",omitempty"` // TODO(crawshaw): replace with MachineStatus
 
 	// Capabilities are capabilities that the node has.

tailcfg/tailcfg_clone.go

@@ -93,7 +93,6 @@ var _NodeCloneNeedsRegeneration = Node(struct {
 	PrimaryRoutes                 []netip.Prefix
 	LastSeen                      *time.Time
 	Online                        *bool
-	KeepAlive                     bool
 	MachineAuthorized             bool
 	Capabilities                  []string
 	UnsignedPeerAPIOnly           bool

tailcfg/tailcfg_test.go

@@ -347,7 +347,7 @@ func TestNodeEqual(t *testing.T) {
 		"Key", "KeyExpiry", "KeySignature", "Machine", "DiscoKey",
 		"Addresses", "AllowedIPs", "Endpoints", "DERP", "Hostinfo",
 		"Created", "Cap", "Tags", "PrimaryRoutes",
-		"LastSeen", "Online", "KeepAlive", "MachineAuthorized",
+		"LastSeen", "Online", "MachineAuthorized",
 		"Capabilities",
 		"UnsignedPeerAPIOnly",
 		"ComputedName", "computedHostIfDifferent", "ComputedNameWithHost",

tailcfg/tailcfg_view.go

@@ -168,7 +168,6 @@ func (v NodeView) Online() *bool {
 	return &x
 }
 
-func (v NodeView) KeepAlive() bool                   { return v.ж.KeepAlive }
 func (v NodeView) MachineAuthorized() bool           { return v.ж.MachineAuthorized }
 func (v NodeView) Capabilities() views.Slice[string] { return views.SliceOf(v.ж.Capabilities) }
 func (v NodeView) UnsignedPeerAPIOnly() bool         { return v.ж.UnsignedPeerAPIOnly }
@@ -210,7 +209,6 @@ var _NodeViewNeedsRegeneration = Node(struct {
 	PrimaryRoutes                 []netip.Prefix
 	LastSeen                      *time.Time
 	Online                        *bool
-	KeepAlive                     bool
 	MachineAuthorized             bool
 	Capabilities                  []string
 	UnsignedPeerAPIOnly           bool