Structure only, no behaviour change. The settings and loadConfig move from
main()'s locals to PointerConfig (pointer/helper/pointer_config.h) with the
same defaults, clamps, and parsing; ReadConfig, ConfDouble, and ParseIgnore
move with them. main() uses them as cfg.<name>.
Head follow and gaze mode stay runtime state. Load only records POINTER_FOLLOW
and POINTER_GAZE; applyConfig, run after each Load (at startup and on
"reload"), turns them on or off when the setting changed, as before, so a
"follow" or "gaze" command still wins until the setting itself changes.
POINTER_LASER_WIDTH is still read once at startup.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
