Flexible lanes load slower; purge at the previous filament's temperature

- flex_lanes.cfg: a 5 s poller sets SET_LONG_MOVE_SPEED to 50 mm/s (AFC's
  minimum) for lanes whose material is TPU/TPE/flex and back to the
  configured long_moves_speed otherwise; reapplied after a restart.
- BLOBIFIER_CHECKED: remembers the temperature of the filament in the
  nozzle (saved nozzle_last_temp). When it is more than flush_margin
  (10C) above the new filament's, the purge runs at that temperature and
  the nozzle cools back afterwards, so the leftover melts out (seen: ASA
  leftover with TPU loaded at 210C).

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

macros/klipper-macros.cfg

@@ -38,6 +38,7 @@
 [include afc/lane_tools.cfg]
 [include afc/purge_check.cfg]
 [include afc/purge_until_empty.cfg]
+[include afc/flex_lanes.cfg]             # TPU/TPE lanes: slower long moves
 
 # Pressure advance per lane/spool (bd_pressure + Spoolman)
 [include pressure_advance/bd_pressure.cfg]   # [bdpressure bd_pa] and the vendor PA_CALIBRATE macros