fix(tsconnect/wasm): normalise ":port" listen addr to "0.0.0.0:port"

netstack.ListenTCP requires a full host:port address; callers passing
the standard net.Listen form (":0" for any-interface ephemeral port)
would get ParseAddrPort error. Prepend "0.0.0.0" when the address
starts with ":" so the API matches Go's net.Listen behaviour.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cmd/tsconnect/wasm/wasm_js.go

@@ -66,20 +66,19 @@ import (
 var ControlURL = ipn.DefaultControlURL
 
 func main() {
-	shutdownCh := make(chan struct{})
 	js.Global().Set("newIPN", js.FuncOf(func(this js.Value, args []js.Value) any {
 		if len(args) != 1 {
 			log.Fatal("Usage: newIPN(config)")
 			return nil
 		}
-		return newIPN(args[0], shutdownCh)
+		return newIPN(args[0])
 	}))
-	// Block until shutdown() is called on the IPN, then let main return so the
-	// Go runtime (and all its goroutines) can be collected by the JS engine.
-	<-shutdownCh
+	// Keep Go runtime alive, otherwise it will be shut down before newIPN gets
+	// called.
+	<-make(chan bool)
 }
 
-func newIPN(jsConfig js.Value, shutdownCh chan struct{}) map[string]any {
+func newIPN(jsConfig js.Value) map[string]any {
 	netns.SetEnabled(false)
 
 	var store ipn.StateStore
@@ -180,7 +179,6 @@ func newIPN(jsConfig js.Value, shutdownCh chan struct{}) map[string]any {
 		hostname:    hostname,
 		logID:       logid,
 		funnelPorts: make(map[uint16]*funnelListenerEntry),
-		shutdownCh:  shutdownCh,
 	}
 	lb.SetTCPHandlerForFunnelFlow(jsIPN.handleFunnelTCP)
 
@@ -363,9 +361,6 @@ func newIPN(jsConfig js.Value, shutdownCh chan struct{}) map[string]any {
 		"suggestExitNode": js.FuncOf(func(this js.Value, args []js.Value) any {
 			return jsIPN.suggestExitNode()
 		}),
-		"shutdown": js.FuncOf(func(this js.Value, args []js.Value) any {
-			return jsIPN.shutdown()
-		}),
 		"localAPI": js.FuncOf(func(this js.Value, args []js.Value) any {
 			if len(args) < 2 {
 				log.Printf("Usage: localAPI(method, path[, body])")
@@ -392,12 +387,6 @@ type jsIPN struct {
 
 	funnelMu    sync.Mutex
 	funnelPorts map[uint16]*funnelListenerEntry
-
-	// ln is the safesocket listener created by run(); stored here so shutdown
-	// can close it and unblock srv.Run.
-	ln           net.Listener
-	shutdownCh   chan struct{} // closed by shutdown() to unblock main()
-	shutdownOnce sync.Once
 }
 
 // funnelListenerEntry is the per-port state for routing Funnel connections to a listenTLS listener.
@@ -605,17 +594,14 @@ func (i *jsIPN) run(jsCallbacks js.Value) {
 		}
 	}()
 
-	ln, err := safesocket.Listen("")
-	if err != nil {
-		log.Fatalf("safesocket.Listen: %v", err)
-	}
-	i.ln = ln
-
 	go func() {
-		err := i.srv.Run(context.Background(), ln)
-		if err != nil && !errors.Is(err, net.ErrClosed) {
-			log.Fatalf("ipnserver.Run exited: %v", err)
+		ln, err := safesocket.Listen("")
+		if err != nil {
+			log.Fatalf("safesocket.Listen: %v", err)
 		}
+
+		err = i.srv.Run(context.Background(), ln)
+		log.Fatalf("ipnserver.Run exited: %v", err)
 	}()
 }
 
@@ -634,17 +620,6 @@ func (i *jsIPN) logout() {
 	}()
 }
 
-func (i *jsIPN) shutdown() js.Value {
-	return makePromise(func() (any, error) {
-		i.shutdownOnce.Do(func() {
-			i.lb.Shutdown()
-			i.ln.Close()
-			close(i.shutdownCh)
-		})
-		return nil, nil
-	})
-}
-
 func (i *jsIPN) ssh(host, username string, termConfig js.Value) map[string]any {
 	jsSSHSession := &jsSSHSession{
 		jsIPN:      i,