feat: Filament Track Switch (H2-series O2L-FTS) support

The Filament Track Switch (H2-series accessory, product code O2L-FTS) feeds
every AMS to both extruders through a two-track switch. Port full support
across the device layer, project config, and GUI.

Device / config:
- Model the switch-aware AMS binding (the set of extruders an AMS can feed
  and which input track A/B feeds it), switch readiness, the O2L-FTS firmware
  module, and the fun2 capability bit for checking a slice against installed
  hardware.
- Register has_filament_switcher and enable_filament_dynamic_map as project
  config that persists with the project and restores from a saved 3mf, and
  force both back to false on every project/printer/CLI load path. Live
  device sync is the only thing that sets them true.

GUI:
- Sidebar sync activates the switch from live device state, attributes each
  AMS to the extruder its input track feeds, shows a floating status icon
  (ready / not-calibrated), and surfaces a one-time tip / not-calibrated
  warning.
- Send dialog gains a non-blocking slice-vs-hardware mismatch warning and a
  blocking error when a slice needs dynamic nozzle mapping but the switch is
  missing or not set up.
- AMS load/unload guards, AMS-view routing glyph + un-calibrated banner +
  hidden external-spool road, and mapping-popup external-spool lockout.
- Filament pickers collapse the per-extruder split into a single deduplicated
  "AMS filaments" group with a smart-assign toggle when the switch is ready.
- Firmware-upgrade panel lists the O2L-FTS accessory and its version.
- Device-provided filament-change steps (ams.cfs) drive the change-step
  display when firmware sends them, including the three switch steps.
- "Load current filament" asks which extruder to feed via a
  FeedDirectionDialog when the switch is calibrated.

Inert without the accessory: every path is gated on the switch being
installed (MQTT aux bit 29, default off) or ready, both project flags default
false, and the per-extruder AMS attribution is byte-identical, so AMS state,
the send/load UI, and sliced g-code are unchanged for every printer that does
not report a Filament Track Switch.

src/slic3r/GUI/FilamentGroupPopup.cpp

@@ -174,6 +174,9 @@ FilamentGroupPopup::FilamentGroupPopup(wxWindow *parent) : PopupWindow(parent, w
         button_labels[idx]->Bind(wxEVT_LEAVE_WINDOW, [this](auto &) { UpdateButtonStatus(); });
     }
 
+    // Smart filament assign section
+    MakeSmartFilamentSection(top_sizer, horizontal_margin, vertical_padding);
+
     {
         wxBoxSizer *button_sizer = new wxBoxSizer(wxHORIZONTAL);
         // ORCA Unified hyperlinks
@@ -257,6 +260,7 @@ void FilamentGroupPopup::Init()
         SetFilamentMapMode(m_mode);
     }
 
+    UpdateSmartFilamentSection();
     UpdateButtonStatus();
     GUI::wxGetApp().UpdateDarkUIWin(this);
 }
@@ -408,4 +412,65 @@ void FilamentGroupPopup::UpdateButtonStatus(int hover_idx)
     Fit();
 }
 
+void FilamentGroupPopup::MakeSmartFilamentSection(wxSizer *top_sizer, int horizontal_margin, int vertical_padding)
+{
+    m_smart_filament_panel = new StaticBox(this, wxID_ANY, wxDefaultPosition, wxDefaultSize, 0);
+    m_smart_filament_panel->SetCornerRadius(FromDIP(4));
+    m_smart_filament_panel->SetBorderWidth(FromDIP(1));
+    m_smart_filament_panel->SetBorderColor(wxColour("#CECECE"));
+    m_smart_filament_panel->SetBackgroundColor(StateColor(std::pair<wxColour, int>(wxColour("#F8F8F8"), StateColor::Normal)));
+
+    auto *label = new Label(m_smart_filament_panel, _L("Enable smart filament assign: Assign one filament to multiple nozzles to maximize savings"));
+    label->SetFont(Label::Body_12);
+    label->SetForegroundColour(GreyColor);
+    label->SetBackgroundColour(wxColour("#F8F8F8"));
+    label->Wrap(FromDIP(240));
+
+    m_smart_filament_switch = new SwitchButton(m_smart_filament_panel);
+    m_smart_filament_switch->Bind(wxEVT_TOGGLEBUTTON, &FilamentGroupPopup::OnSmartFilamentToggle, this);
+#ifdef __WXOSX__
+    // wxEVT_TOGGLEBUTTON event not handled well by PopupWindow on MacOS
+    // we bind a wxEVT_LEFT_DOWN event as a workaround
+    m_smart_filament_switch->Bind(wxEVT_LEFT_DOWN, [this](wxMouseEvent &) {
+        wxCommandEvent evt(wxEVT_TOGGLEBUTTON);
+        evt.SetInt(!m_smart_filament_switch->GetValue());
+        m_smart_filament_switch->Command(evt);
+    });
+#endif
+
+    auto *panel_sizer = new wxBoxSizer(wxHORIZONTAL);
+    panel_sizer->Add(label, 1, wxALIGN_CENTER_VERTICAL | wxALL, FromDIP(10));
+    panel_sizer->Add(m_smart_filament_switch, 0, wxALIGN_CENTER_VERTICAL | wxRIGHT, FromDIP(10));
+    m_smart_filament_panel->SetSizer(panel_sizer);
+
+    top_sizer->Add(m_smart_filament_panel, 0, wxEXPAND | wxLEFT | wxRIGHT, horizontal_margin);
+    m_smart_filament_spacer = top_sizer->AddSpacer(vertical_padding);
+
+    // Hidden by default; shown in Init() when the filament track switch is ready
+    m_smart_filament_panel->Show(false);
+    m_smart_filament_spacer->Show(false);
+}
+
+void FilamentGroupPopup::OnSmartFilamentToggle(wxCommandEvent &event)
+{
+    auto &config           = wxGetApp().preset_bundle->project_config;
+    auto *dynamic_filament = dynamic_cast<ConfigOptionBool *>(config.option("enable_filament_dynamic_map"));
+    if (dynamic_filament) { dynamic_filament->value = m_smart_filament_switch->GetValue(); }
+    plater_ref->update();
+    event.Skip();
+}
+
+void FilamentGroupPopup::UpdateSmartFilamentSection()
+{
+    bool show = wxGetApp().sidebar().is_fila_switch_ready();
+    m_smart_filament_panel->Show(show);
+    m_smart_filament_spacer->Show(show);
+
+    if (show) {
+        auto &config           = wxGetApp().preset_bundle->project_config;
+        auto *dynamic_filament = dynamic_cast<ConfigOptionBool *>(config.option("enable_filament_dynamic_map"));
+        if (dynamic_filament) { m_smart_filament_switch->SetValue(dynamic_filament->value); }
+    }
+}
+
 }} // namespace Slic3r::GUI