Plot data with gnuplot

Plot data from the most recent interaction context using gnuplot. Generate a PNG image with a transparent background and output it as a markdown image so it renders inline.

How to plot

1. Extract or derive plottable data from the current context.
2. If the Emacs foreground color is not already known from a previous plot in this session, query it:

   emacsclient --eval '
   (face-foreground (quote default))'
   

   This returns a hex color like "#eeffff". Reuse it for all subsequent plots.
3. Write a gnuplot script to a temporary file using that color.
4. Run gnuplot on the script.
5. Output the result as a markdown image on its own line:

   ![description](/tmp/agent-plot-XXXX.png)