Stop using bdwidth while printing, work without it

bdwidth's motion reading stays at 0, its per-reading width compensation
made the flow jump between 77 and 119%, and a USB dropout shut down
Klipper. PRINT_START no longer enables it. _PRINT_CLEANUP,
BLOBIFIER_CHECKED and PURGE_UNTIL_EMPTY only send bdwidth commands when
[bdwidth fila_width_0] exists, and bdwidth_status reports present: False
with neutral values when it is not configured, so the section can be
removed from printer.cfg.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

macros/print/print_start_end.cfg

@@ -203,10 +203,9 @@ gcode:
 
     _AFC_STORE_HOME_REFERENCE
 
-    # Width only (flow compensation and runout when no filament is measured).
-    # The CCD motion reading stays at 0 (actual_total_move:0), so motion mode
-    # (ENABLE_MOTION / ENABLE_ALL) only gives false "Rounout" messages.
-    SET_BDWIDTH NAME=fila_width_0 COMMAND=ENABLE_WIDTH
+    # bdwidth is not used while printing: its motion reading stays at 0 and its
+    # per-reading width compensation made the flow jump between 77 and 119%.
+    # To use it again: SET_BDWIDTH NAME=fila_width_0 COMMAND=ENABLE_WIDTH
     
     _status_printing
 
@@ -252,7 +251,9 @@ gcode:
     TURN_OFF_HEATERS
     iHEATER_OFF                                     ; stops the chamber heater control loop too
     M107
+    {% if 'bdwidth fila_width_0' in printer %}
     SET_BDWIDTH NAME=fila_width_0 COMMAND=DISABLE   ; also sets M221 S100
+    {% endif %}
     M221 S100
     BED_MESH_CLEAR
     SET_SKEW CLEAR=1