Wait for the toolchange temperature on the wipe tower

Adds a printer option that picks up the new tool without a blocking temperature
wait, travels to the wipe tower, and waits there right before purging, parked
beside the tower so the ooze from the heat-up lands next to it rather than on the
model. The incoming filament's target is raised ahead of the tool change, so the
heat-up overlaps both the change itself and the travel to the tower.

Off by default, and only offered for multi-extruder printers using a Type 2 wipe
tower; the generic toolchanger profile enables it.

src/libslic3r/Print.cpp

@@ -282,6 +282,14 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "wipe_tower_x"
             || opt_key == "wipe_tower_y"
             || opt_key == "wipe_tower_rotation_angle") {
+            // The tower gcode itself is position-independent (position and rotation are applied
+            // at export), except that the wait_for_temp_on_wipe_tower park bakes a bed-relative
+            // side choice into it (WipeTower2::toolchange_Change) — regenerate it when the tower
+            // moves. Gating on the old config is safe: both inputs of wait_for_temp_enabled
+            // invalidate psWipeTower themselves when they are part of the same diff.
+            if ((opt_key == "wipe_tower_x" || opt_key == "wipe_tower_y" || opt_key == "wipe_tower_rotation_angle")
+                && WipeTower2::wait_for_temp_enabled(m_config))
+                steps.emplace_back(psWipeTower);
             steps.emplace_back(psSkirtBrim);
         } else if (
                opt_key == "slicing_pipeline_plugin"
@@ -382,6 +390,7 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "wiping_volumes_extruders"
             || opt_key == "enable_filament_ramming"
             || opt_key == "tool_change_on_wipe_tower"
+            || opt_key == "wait_for_temp_on_wipe_tower"
             || opt_key == "purge_in_prime_tower"
             || opt_key == "z_offset"
             || opt_key == "support_multi_bed_types"