all: construct new System values with an event bus pre-populated

Although, at the moment, we do not yet require an event bus to be present, as
we start to add more pieces we will want to ensure it is always available.  Add
a new constructor and replace existing uses of new(tsd.System) throughout.
Update generated files for import changes.

Updates #15160

Change-Id: Ie5460985571ade87b8eac8b416948c7f49f0f64b
Signed-off-by: M. J. Fromberger <fromberger@tailscale.com>

cmd/k8s-operator/depaware.txt

@@ -939,7 +939,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/
      💣 tailscale.com/util/deephash                                  from tailscale.com/ipn/ipnlocal+
    L 💣 tailscale.com/util/dirwalk                                   from tailscale.com/metrics+
         tailscale.com/util/dnsname                                   from tailscale.com/appc+
-        tailscale.com/util/eventbus                                  from tailscale.com/tsd
+        tailscale.com/util/eventbus                                  from tailscale.com/tsd+
         tailscale.com/util/execqueue                                 from tailscale.com/appc+
         tailscale.com/util/goroutines                                from tailscale.com/ipn/ipnlocal
         tailscale.com/util/groupmember                               from tailscale.com/client/web+

cmd/tailscaled/depaware.txt

@@ -391,7 +391,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
      💣 tailscale.com/util/deephash                                  from tailscale.com/ipn/ipnlocal+
    L 💣 tailscale.com/util/dirwalk                                   from tailscale.com/metrics+
         tailscale.com/util/dnsname                                   from tailscale.com/appc+
-        tailscale.com/util/eventbus                                  from tailscale.com/cmd/tailscaled+
+        tailscale.com/util/eventbus                                  from tailscale.com/tsd+
         tailscale.com/util/execqueue                                 from tailscale.com/control/controlclient+
         tailscale.com/util/goroutines                                from tailscale.com/ipn/ipnlocal
         tailscale.com/util/groupmember                               from tailscale.com/client/web+

cmd/tailscaled/tailscaled.go

@@ -62,7 +62,6 @@ import (
 	"tailscale.com/types/logger"
 	"tailscale.com/types/logid"
 	"tailscale.com/util/clientmetric"
-	"tailscale.com/util/eventbus"
 	"tailscale.com/util/multierr"
 	"tailscale.com/util/osshare"
 	"tailscale.com/version"
@@ -375,11 +374,9 @@ var debugMux *http.ServeMux
 func run() (err error) {
 	var logf logger.Logf = log.Printf
 
-	sys := new(tsd.System)
-
 	// Install an event bus as early as possible, so that it's
 	// available universally when setting up everything else.
-	sys.Set(eventbus.New())
+	sys := tsd.NewSystemWithEventBus()
 
 	// Parse config, if specified, to fail early if it's invalid.
 	var conf *conffile.Config
@@ -718,6 +715,7 @@ var tstunNew = tstun.New
 
 func tryEngine(logf logger.Logf, sys *tsd.System, name string) (onlyNetstack bool, err error) {
 	conf := wgengine.Config{
+		EventBus:      sys.Bus.Get(),
 		ListenPort:    args.port,
 		NetMon:        sys.NetMon.Get(),
 		HealthTracker: sys.HealthTracker(),

cmd/tailscaled/tailscaled_windows.go

@@ -328,7 +328,7 @@ func beWindowsSubprocess() bool {
 		log.Printf("Error pre-loading \"%s\": %v", fqWintunPath, err)
 	}
 
-	sys := new(tsd.System)
+	sys := tsd.NewSystemWithEventBus()
 	netMon, err := netmon.New(log.Printf)
 	if err != nil {
 		log.Fatalf("Could not create netMon: %v", err)

cmd/tsconnect/wasm/wasm_js.go

@@ -100,7 +100,7 @@ func newIPN(jsConfig js.Value) map[string]any {
 	logtail := logtail.NewLogger(c, log.Printf)
 	logf := logtail.Logf
 
-	sys := new(tsd.System)
+	sys := tsd.NewSystemWithEventBus()
 	sys.Set(store)
 	dialer := &tsdial.Dialer{Logf: logf}
 	eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{