Sizes the curses viewfinder box to match the print output's character
grid (A4/roll-paper target dims) instead of always filling the
terminal, and always centers the box. Defaults to true.
ascii.conf exposes ascii-image-converter's dimension/complexity/map/
grayscale/negative/flip options (color and braille stay out since they
rely on ANSI/multi-byte Unicode that txt2printr.sh's raw print path
can't render). keybinds.conf lets exec-cycle.sh's capture/brightness/
exposure/reset keys be rebound instead of hardcoded, matched
case-insensitively; the on-screen hint bar renders from the same
config so it never drifts out of sync with the actual bindings.