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/agent/session.go

@@ -33,7 +33,8 @@ func (a *Agent) runTerminal(parent context.Context, sid, user, dir string) {
 }
 
 // runForward dials 127.0.0.1:port on the client and bridges it to the session,
-// giving the host a reverse TCP tunnel over the same long-poll transport.
+// giving the host a reverse TCP tunnel over the agent's link to the server:
+// the WebSocket, or the long polls without one.
 func (a *Agent) runForward(parent context.Context, sid string, port int) {
 	d := net.Dialer{Timeout: 10 * time.Second}
 	conn, err := d.DialContext(parent, "tcp", net.JoinHostPort("127.0.0.1", strconv.Itoa(port)))
@@ -92,7 +93,8 @@ func (a *Agent) bridgeStream(parent context.Context, sid string, rw io.ReadWrite
 	}
 }
 
-// pollIn performs one downstream long-poll and applies the frames.
+// pollIn takes the next input - pushed on the WebSocket, else by a long
+// poll - and applies the frames.
 // Returns false when the session is gone and the loop should stop.
 func (a *Agent) pollIn(ctx context.Context, sid string, w io.Writer, onResize func(cols, rows uint16)) bool {
 	// On the WebSocket the input comes pushed; if it drops, by a long poll.