PCjs Debugger doesn't support Carriage Returns across serial I/O to reset current line to first column

[ecm-pushbx]

I figured out that my debugger application can connect to the PCjs Debugger window via serial I/O on the COM1 port. Details in https://pushbx.org/ecm/dokuwiki/doku.php?id=blog:pushbx:2022:1111_lcdebug_image_for_use_with_pcjs.org#comment_51a19d7eaf2539aa96ba0d557229eb0f

However, the application's line input handler uses lone CRs (without subsequent LFs) to reset the current line to the first column, ready to be overwritten by new content. This is not supported by the PCjs Debugger window which seems to interpret every CR as a complete linebreak, beyond only returning the carriage.