feat(engine): wire the per-filament volume-map producer pipeline

- Print::update_filament_maps_to_config takes filament/volume/nozzle
  maps, backfills an empty volume map from extruder types, rebuilds
  filament_map_2, re-expands the per-filament variant arrays, and
  recomputes retract overrides keyed by resolved slots
- grouping writes its result back in every non-sequential mode;
  manual multi-nozzle grouping validates the user mapping and raises a
  translatable error on deviation; the engine's concrete volume
  assignment is deliberately not merged yet (per-filament arrays are
  already consumed by filament id, so materializing High Flow now
  would change motion before the layer-aware resolvers land)
- Print::apply treats the three map keys as engine outputs in auto
  modes (erased from the diff and adopted), compares them against used
  filaments in manual mode, and keeps the pre-expansion snapshot in
  sync with the late normalization pass so rebuilt headers reflect the
  sliced state instead of resurrecting stale values
- volume/nozzle maps and extruder_nozzle_stats join the invalidation
  group of filament_map (wipe tower + skirt/brim)
- PresetBundle composes full configs with an optional per-filament
  volume map (plate map, else defaults derived from each extruder's
  flow type); project config keeps the map sized across filament
  count changes
- PartPlate stores per-plate volume/nozzle maps; Plater injects them
  at every slice-composition site (incl. g-code reload and wipe-tower
  estimation); BackgroundSlicingProcess reads engine results back to
  the plate in auto modes
- per-filament map trust guards relaxed to size-match everywhere now
  that every producer sizes the map; single-filament explicit flow
  assignments are honored
- tests: grouping volume maps stay concrete, merge semantics of
  update_used_filament_values, single-filament override honoring

Motion g-code is byte-identical fleet-wide including Hybrid projects
(19-fixture gate + repro determinism double-slice). Header deltas:
the map keys now dump real values, and stale pre-normalization values
(e.g. enable_prime_tower on single-used-filament prints) no longer
leak into the config block.

src/slic3r/GUI/PartPlate.cpp

@@ -319,6 +319,18 @@ std::vector<int> PartPlate::get_real_filament_maps(const DynamicConfig& g_config
 	return g_maps;
 }
 
+std::vector<int> PartPlate::get_real_filament_volume_maps(const DynamicConfig& g_config, bool* use_global_param) const
+{
+	auto maps = get_filament_volume_maps();
+	if (!maps.empty()) {
+		if (use_global_param) { *use_global_param = false; }
+		return maps;
+	}
+	auto g_maps = g_config.option<ConfigOptionInts>("filament_volume_map")->values;
+	if (use_global_param) { *use_global_param = true; }
+	return g_maps;
+}
+
 FilamentMapMode PartPlate::get_real_filament_map_mode(const DynamicConfig& g_config, bool* use_global_param) const
 {
 	auto mode = get_filament_map_mode();
@@ -3506,8 +3518,16 @@ int PartPlate::load_gcode_from_file(const std::string& filename)
 	int ret = 0;
 
 	// process gcode
+	auto& preset_bundle = wxGetApp().preset_bundle;
 	std::vector<int>   filament_maps = this->get_filament_maps();
-	DynamicPrintConfig full_config   = wxGetApp().preset_bundle->full_config(false, filament_maps);
+	// Inject the plate's volume map (or the per-extruder defaults) exactly like the apply-time
+	// composition, so the config applied over the loaded slice result matches the next
+	// background-process apply and does not invalidate the embedded g-code.
+	std::vector<int> f_volume_maps = this->get_filament_volume_maps();
+	if (f_volume_maps.empty()) {
+		f_volume_maps = preset_bundle->get_default_nozzle_volume_types_for_filaments(filament_maps);
+	}
+	DynamicPrintConfig full_config   = preset_bundle->full_config(false, filament_maps, f_volume_maps);
 	full_config.apply(m_config, true);
 	m_print->apply(*m_model, full_config, false);
 	//BBS: need to apply two times, for after the first apply, the m_print got its object,
@@ -3814,6 +3834,40 @@ void PartPlate::clear_filament_map()
         m_config.erase("filament_map");
 }
 
+std::vector<int> PartPlate::get_filament_volume_maps() const
+{
+    std::string key = "filament_volume_map";
+    if (m_config.has(key))
+        return m_config.option<ConfigOptionInts>(key)->values;
+
+    return {};
+}
+
+void PartPlate::set_filament_volume_maps(const std::vector<int>& f_maps)
+{
+    m_config.option<ConfigOptionInts>("filament_volume_map", true)->values = f_maps;
+}
+
+void PartPlate::clear_filament_volume_map()
+{
+    if (m_config.has("filament_volume_map"))
+        m_config.erase("filament_volume_map");
+}
+
+std::vector<int> PartPlate::get_filament_nozzle_maps() const
+{
+    std::string key = "filament_nozzle_map";
+    if (m_config.has(key))
+        return m_config.option<ConfigOptionInts>(key)->values;
+
+    return {};
+}
+
+void PartPlate::set_filament_nozzle_maps(const std::vector<int>& f_maps)
+{
+    m_config.option<ConfigOptionInts>("filament_nozzle_map", true)->values = f_maps;
+}
+
 void PartPlate::clear_filament_map_mode()
 {
     if (m_config.has("filament_map_mode"))
@@ -4247,7 +4301,14 @@ void PartPlateList::set_default_wipe_tower_pos_for_plate(int plate_idx, bool ini
     coordf_t plate_bbox_y_max_local_coord = plate_bbox_2d.max(1) - plate_origin(1);
 
     std::vector<int> filament_maps = part_plate->get_real_filament_maps(proj_cfg);
-    DynamicPrintConfig full_config = wxGetApp().preset_bundle->full_config(false, filament_maps);
+    // Keep this composition consistent with the apply-time injection (plate volume map, else
+    // per-extruder defaults); the config below currently only feeds scalar reads, but a
+    // divergent volume map would silently mis-resolve any future per-filament read here.
+    std::vector<int> f_volume_maps = part_plate->get_filament_volume_maps();
+    if (f_volume_maps.empty()) {
+        f_volume_maps = wxGetApp().preset_bundle->get_default_nozzle_volume_types_for_filaments(filament_maps);
+    }
+    DynamicPrintConfig full_config = wxGetApp().preset_bundle->full_config(false, filament_maps, f_volume_maps);
     const DynamicPrintConfig &print_cfg = wxGetApp().preset_bundle->prints.get_edited_preset().config;
     float w = dynamic_cast<const ConfigOptionFloat *>(print_cfg.option("prime_tower_width"))->value;
     float v = dynamic_cast<const ConfigOptionFloat *>(full_config.option("prime_volume"))->value;