Replaces per-frame fswebcam process spawns with a persistent OpenCV/v4l2
capture handle for the highest achievable refresh rate, while still
shelling out to ascii-image-converter for conversion and txt2printr.sh
for printing. Renders a bordered live preview with a status/keybind-help
bar via curses, works on a plain TTY with no graphical environment.
Reuses webcam.conf/ascii.conf/keybinds.conf, parsed as plain key=value
(not sourced, so a config file can no longer execute arbitrary code).
Brightness/exposure now go through v4l2-ctl with percentage mapped onto
each control's actual min/max range; added DEVICE/BRIGHTNESS_CTRL_ID/
EXPOSURE_CTRL_ID to webcam.conf and KEY_QUIT to keybinds.conf for this,
kept separate from the bash-oriented keys so the existing bash scripts
are unaffected. Bash scripts are left in place as a fallback.
New deps: python-opencv, v4l-utils.
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.
Amir Alexander Abdelbaki