Remove orphaned relay address package and legacy HelloResponse handling

shared/relay/messages/address/address.go

@@ -1,21 +0,0 @@
-// Deprecated: This package is deprecated and will be removed in a future release.
-package address
-
-import (
-	"bytes"
-	"encoding/gob"
-	"fmt"
-)
-
-type Address struct {
-	URL string
-}
-
-func (addr *Address) Marshal() ([]byte, error) {
-	var buf bytes.Buffer
-	enc := gob.NewEncoder(&buf)
-	if err := enc.Encode(addr); err != nil {
-		return nil, fmt.Errorf("encode Address: %w", err)
-	}
-	return buf.Bytes(), nil
-}

shared/relay/messages/message.go

@@ -14,9 +14,10 @@ const (
 	CurrentProtocolVersion = 1
 
 	MsgTypeUnknown MsgType = 0
-	// Deprecated: Use MsgTypeAuth instead.
-	MsgTypeHello = 1
-	// Deprecated: Use MsgTypeAuthResponse instead.
+	// MsgTypeHello and MsgTypeHelloResponse are the removed legacy handshake
+	// message types. They are retained only to reserve wire values 1 and 2 so
+	// the values are never reused; the server rejects both.
+	MsgTypeHello         = 1
 	MsgTypeHelloResponse = 2
 	MsgTypeTransport     = 3
 	MsgTypeClose         = 4
@@ -130,7 +131,6 @@ func DetermineServerMessageType(msg []byte) (MsgType, error) {
 	msgType := MsgType(msg[1])
 	switch msgType {
 	case
-		MsgTypeHelloResponse,
 		MsgTypeAuthResponse,
 		MsgTypeTransport,
 		MsgTypeClose,

shared/relay/messages/message_test.go

@@ -5,8 +5,7 @@ import (
 )
 
 func TestDetermineClientMessageTypeRejectsHello(t *testing.T) {
-	// The deprecated Hello message (type 1) is no longer accepted by the
-	// server, closing the pre-auth gob decode path (GHSA-v5w2-pqxj-6r94).
+	// The reserved legacy Hello message (type 1) must be rejected by the server.
 	msg := []byte{byte(CurrentProtocolVersion), byte(MsgTypeHello)}
 	if _, err := DetermineClientMessageType(msg); err == nil {
 		t.Fatalf("expected hello message type to be rejected")