docs: http-lp forwarding goes over the agent's WebSocket, by long polls only without one - said so in the panel, the code and the README

internal/proto/proto.go

@@ -1,8 +1,8 @@
 // Package proto describes the wire messages shared by the server and the agent.
 //
-// All agent<->server traffic is plain JSON over HTTP(S) long-polling so it
-// survives NAT and restrictive egress firewalls: the agent only ever makes
-// outbound requests.
+// All agent<->server traffic is plain JSON, on a WebSocket the agent opens or,
+// where that does not get through, over HTTP(S) long polls, so it survives
+// NAT and restrictive egress firewalls: the agent only ever connects out.
 package proto
 
 import "strings"
@@ -11,7 +11,7 @@ import "encoding/json"
 
 // Control poll message types (server -> agent, returned from /api/agent/poll).
 const (
-	// CtrlIdle is returned when the long-poll times out with nothing to do.
+	// CtrlIdle is returned when the control poll times out with nothing to do.
 	CtrlIdle = "idle"
 	// CtrlOpenTerminal tells the agent to spawn a PTY for the session id.
 	CtrlOpenTerminal = "open_terminal"
@@ -56,7 +56,8 @@ type EnrollResponse struct {
 	Token   string `json:"token"`
 }
 
-// ControlMessage is the body returned by the control long-poll.
+// ControlMessage is a command for the agent: on the WebSocket, or the body of
+// the control long poll.
 type ControlMessage struct {
 	Type      string     `json:"type"`
 	SessionID string     `json:"session_id,omitempty"`