fix: Set http2 based on prop

pkg/server/interfaces.go

@@ -19,6 +19,10 @@ type Config struct {
 	// GZIP compression support
 	GZIP bool
 
+	// HTTP2 enables HTTP/2 with the Extended CONNECT protocol (RFC 8441) for WebSocket support.
+	// Requires TLS; pair with SSLCert/SSLKey, SelfSignedSSL, or AutoTLS.
+	HTTP2 bool
+
 	// TLS/HTTPS configuration options (mutually exclusive)
 	// Option 1: Provide certificate and key files directly
 	SSLCert string

pkg/server/manager.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"syscall"
@@ -461,15 +462,38 @@ func newInstance(cfg Config) (*serverInstance, error) {
 	}
 
 	// Create gracefulServer
+	httpServer := &http.Server{
+		Addr:         addr,
+		Handler:      handler,
+		ReadTimeout:  cfg.ReadTimeout,
+		WriteTimeout: cfg.WriteTimeout,
+		IdleTimeout:  cfg.IdleTimeout,
+		TLSConfig:    tlsConfig,
+	}
+
+	// Enable HTTP/2 with Extended CONNECT (RFC 8441) for WebSocket-over-H2 support.
+	// The GODEBUG=http2xconnect=1 flag is read by net/http's init(); setting it here
+	// ensures it propagates to subprocesses and any future process restarts.
+	// For the current process, set GODEBUG=http2xconnect=1 in the environment before launch.
+	if cfg.HTTP2 {
+		if existing := os.Getenv("GODEBUG"); !strings.Contains(existing, "http2xconnect=1") {
+			if existing == "" {
+				os.Setenv("GODEBUG", "http2xconnect=1")
+			} else {
+				os.Setenv("GODEBUG", existing+",http2xconnect=1")
+			}
+		}
+		if httpServer.HTTP2 == nil {
+			httpServer.HTTP2 = &http.HTTP2Config{}
+		}
+		httpServer.Protocols.SetHTTP2(true)
+		httpServer.Protocols.SetUnencryptedHTTP2(true)
+	} else {
+		httpServer.Protocols.SetHTTP2(false)
+	}
+
 	gracefulSrv := &gracefulServer{
-		server: &http.Server{
-			Addr:         addr,
-			Handler:      handler,
-			ReadTimeout:  cfg.ReadTimeout,
-			WriteTimeout: cfg.WriteTimeout,
-			IdleTimeout:  cfg.IdleTimeout,
-			TLSConfig:    tlsConfig,
-		},
+		server:           httpServer,
 		shutdownTimeout:  cfg.ShutdownTimeout,
 		drainTimeout:     cfg.DrainTimeout,
 		shutdownComplete: make(chan struct{}),