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/afc/flex_lanes.cfg

@@ -0,0 +1,54 @@
+# Flexible filament (TPU, TPE): slower long moves for the lanes holding it.
+#
+# Soft filament can buckle in the long tube at the normal 100-200 mm/s.
+# A poller checks the material of every lane (from Spoolman via AFC) every
+# 5 s and sets the lane's long-move speed: flex_speed for a flexible
+# material, the configured long_moves_speed again when the lane holds
+# something else. Only changes are sent. SET_LONG_MOVE_SPEED is runtime
+# only; after a Klipper restart the poller applies it again.
+#
+# Not covered: the last stretch into the extruder (tool_load_speed in
+# AFC/AFC_Hardware.cfg, 25 mm/s) has no runtime command and is the same
+# for every lane. The purge after the load is already slow (2.5 mm/s).
+
+[gcode_macro _FLEX_LANES_CFG]
+variable_materials: ["tpu", "tpe", "flex"]  # material containing one of these (any case) is flexible
+variable_flex_speed: 50                     # mm/s; AFC's minimum for SET_LONG_MOVE_SPEED is 50
+variable_slowed: ""                         # runtime: comma list of lanes now at flex_speed
+gcode:
+
+[delayed_gcode _FLEX_LANES_POLL]
+initial_duration: 10
+gcode:
+    {% set cfg = printer["gcode_macro _FLEX_LANES_CFG"] %}
+    {% if 'AFC' in printer %}
+      {% set settings = printer.configfile.settings %}
+      {% set default_speed = settings.afc.long_moves_speed|default(150) if 'afc' in settings else 150 %}
+      {% set was = cfg.slowed.split(',')|reject('equalto', '')|list %}
+      {% set now = [] %}
+      {% for lane in printer.AFC.lanes %}
+        {% set key = 'AFC_stepper ' ~ lane %}
+        {% set mat = (printer[key].material if key in printer else '')|default('', true)|string %}
+        {% set ns = namespace(flex=false) %}
+        {% for m in cfg.materials %}
+          {% if m in mat|lower %}
+            {% set ns.flex = true %}
+          {% endif %}
+        {% endfor %}
+        {% if ns.flex %}
+          {% set _ = now.append(lane) %}
+          {% if lane not in was %}
+            SET_LONG_MOVE_SPEED LANE={lane} FWD_SPEED={cfg.flex_speed}
+            RESPOND MSG="{lane} holds {mat}: long moves at {cfg.flex_speed} mm/s (flexible)"
+          {% endif %}
+        {% elif lane in was %}
+          {% set speed = settings[key|lower].long_moves_speed|default(default_speed) if (key|lower) in settings else default_speed %}
+          SET_LONG_MOVE_SPEED LANE={lane} FWD_SPEED={speed}
+          RESPOND MSG="{lane} holds {mat or 'nothing'}: long moves back at {speed} mm/s"
+        {% endif %}
+      {% endfor %}
+      {% if now|join(',') != was|join(',') %}
+        SET_GCODE_VARIABLE MACRO=_FLEX_LANES_CFG VARIABLE=slowed VALUE='"{now|join(',')}"'
+      {% endif %}
+    {% endif %}
+    UPDATE_DELAYED_GCODE ID=_FLEX_LANES_POLL DURATION=5