init work to integrate OrcaSlicer-FullSpectrum fork Integrations up to commit b3c41fda41.

- libslic3r: vendor FilamentMixer; MixedFilamentManager (auto-gen, resolve,
    serialize; manual-pattern / gradient / pointillism); 19 new PrintConfig
    keys; PresetBundle owns the canonical manager with 3MF + AppConfig
    roundtrip and AMS-safe strip+restore; Print owns the slicing-time copy
    with PrintApply auto-regen on color change; TriangleSelector::
    shift_states_above + filament-id remap; inset_idx propagation through
    ExtrusionPath/Loop/MultiPath copy/assign.
  - Slicing: virtual filament IDs in painted regions (same-physical channels
    collapse when mixed_filament_region_collapse is on); ByObject
    collect_filament_data expands mixed slots; pair-cadence + whole-object +
    3+component Local-Z plan generators; LocalZOrderOptimizer utility.
  - GCode + ToolOrdering: LayerTools resolves virtual IDs through wall /
    infill / sparse / solid queries; SameLayerPointillisme in process_layer
    (uniform-segment + grouped per-perimeter-index splitters); WipeTower2
    Local-Z reservation + sub-layer G-code emission; per-layer infill
    filament override.
  - PartPlate: get_extruders* expand virtual slots into physical components;
    CLI path rebuilds a local manager from full_config.
  - GUI: five widget files extracted from FS Plater.cpp (~5000 LOC) —
    MixedMixPreview, MixedGradientSelector + WeightsDialog,
    MixedFilamentColorMapPanel, MixedFilamentColorMatchDialog (ΔE₀₀ recipe
    search), MixedFilamentConfigPanel; Sidebar Mixed Filaments panel
    (drag-reorder, enable/delete, Add Gradient/Pattern/Color); Tab exposure
    of mixed-filament / dithering / per-layer infill-override settings +
    ConfigManipulation visibility and slot-validation rules;
    BBLMixedFilamentBroken / BBLSingleExtruderMixedFilamentRisk
    notifications + slice gate; WipeTowerDialog edits physical P×P
    sub-matrix; bounds-safe extruder_id guards in 3DScene / GLCanvas3D /
    GLGizmoMmuSegmentation; change_filament merge guard and
    on_filaments_delete is_mixed_before_delete propagation.
  - Tests: 4 Catch2 tests for 3MF roundtrip (auto/custom persistence,
    PresetBundle string path, total_filaments stability); full-pipeline
    slice E2E deferred — TODO in file.

Co-authored-by: Rad <radugheorghiu96@gmail.com>
Co-authored-by: Justin Hayes <justinh@rahb.ca>
Co-authored-by: Calogero Guagenti <calogeroguagenti@gmail.com>
Co-authored-by: xSil3nt <ahmedshazin21@gmail.com>
Co-authored-by: ratdoux <62392831+ratdoux@users.noreply.github.com>

Update TriangleSelector.cpp

Co-Authored-By: Rad <radugheorghiu96@gmail.com>
Co-Authored-By: Justin Hayes <justinh@rahb.ca>
Co-Authored-By: Calogero Guagenti <calogeroguagenti@gmail.com>
Co-Authored-By: xSil3nt <ahmedshazin21@gmail.com>
Co-Authored-By: ratdoux <62392831+ratdoux@users.noreply.github.com>

src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp

@@ -179,13 +179,14 @@ void GLGizmoMmuSegmentation::data_changed(bool is_serializing)
 
     ModelObject* model_object = m_c->selection_info()->model_object();
     int prev_extruders_count = int(m_extruders_colors.size());
-    if (prev_extruders_count != wxGetApp().filaments_cnt()) {
-        if (wxGetApp().filaments_cnt() > int(GLGizmoMmuSegmentation::EXTRUDERS_LIMIT))
+    int cur_filaments_count  = int(wxGetApp().preset_bundle->total_filament_count());
+    if (prev_extruders_count != cur_filaments_count) {
+        if (cur_filaments_count > int(GLGizmoMmuSegmentation::EXTRUDERS_LIMIT))
             show_notification_extruders_limit_exceeded();
 
         this->init_extruders_data();
         // Reinitialize triangle selectors because of change of extruder count need also change the size of GLIndexedVertexArray
-        if (prev_extruders_count != wxGetApp().filaments_cnt())
+        if (prev_extruders_count != int(m_extruders_colors.size()))
             this->init_model_triangle_selectors();
     } else if (wxGetApp().plater()->get_extruders_colors() != m_extruders_colors) {
         this->init_extruders_data();
@@ -731,6 +732,8 @@ void GLGizmoMmuSegmentation::init_model_triangle_selectors()
             continue;
 
         int extruder_idx = (mv->extruder_id() > 0) ? mv->extruder_id() - 1 : 0;
+        extruder_idx = std::min(extruder_idx, (int)m_extruders_colors.size() - 1);
+        if (extruder_idx < 0) extruder_idx = 0;
         std::vector<ColorRGBA> ebt_colors;
         ebt_colors.push_back(m_extruders_colors[size_t(extruder_idx)]);
         ebt_colors.insert(ebt_colors.end(), m_extruders_colors.begin(), m_extruders_colors.end());
@@ -753,6 +756,7 @@ void GLGizmoMmuSegmentation::update_triangle_selectors_colors()
         TriangleSelectorPatch* selector = dynamic_cast<TriangleSelectorPatch*>(m_triangle_selectors[i].get());
         int extruder_idx = m_volumes_extruder_idxs[i];
         int extruder_color_idx = std::max(0, extruder_idx - 1);
+        extruder_color_idx = std::min(extruder_color_idx, (int)m_extruders_colors.size() - 1);
         std::vector<ColorRGBA> ebt_colors;
         ebt_colors.push_back(m_extruders_colors[extruder_color_idx]);
         ebt_colors.insert(ebt_colors.end(), m_extruders_colors.begin(), m_extruders_colors.end());
@@ -767,7 +771,8 @@ void GLGizmoMmuSegmentation::update_from_model_object(bool first_update)
     // Extruder colors need to be reloaded before calling init_model_triangle_selectors to render painted triangles
     // using colors from loaded 3MF and not from printer profile in Slicer.
     if (int prev_extruders_count = int(m_extruders_colors.size());
-        prev_extruders_count != wxGetApp().filaments_cnt() || wxGetApp().plater()->get_extruders_colors() != m_extruders_colors)
+        prev_extruders_count != int(wxGetApp().preset_bundle->total_filament_count()) ||
+        wxGetApp().plater()->get_extruders_colors() != m_extruders_colors)
         this->init_extruders_data();
 
     this->init_model_triangle_selectors();