checkpoint: integrate authenticated transports

examples/server.advanced.toml

@@ -1,7 +1,7 @@
 # Advanced server example. Values are placeholders, not credentials.
 
 [server]
-listen = "0.0.0.0:51830"
+listen = "0.0.0.0"
 
 [backend]
 target = "127.0.0.1:51820"
@@ -16,7 +16,7 @@ port = 443
 
 [transports.http3]
 enabled = true
-port = 443
+port = 4443
 path = "/tunnel"
 
 [transports.tls_tcp]