Klipper's G10 retracts only once until a G11, and nothing sends G11 on
this printer: the G10 in PRINT_WARMUP used up the retract, so PRINT_END
never retracted and the nozzle leaked while cooling down.
- _NOZZLE_RETRACT retracts and remembers the amount in the saved
variable nozzle_retract (survives restarts, capped at 15 mm).
PRINT_END retracts 5 mm, PRINT_WARMUP 2 mm, CANCEL_PRINT 5 mm plus the
park/PAUSE retract.
- _NOZZLE_UNRETRACT in PRINT_START pushes it back over the bucket before
the wipe.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>