feat(printer): add cooling filter support flag and expose its toggle

cooling_filter_enabled existed as a config option but was shown nowhere,
and there was no capability flag to gate it. The cooling filter and air
filtration are alternative accessories sharing the same duct, so a
printer declares one or the other.

- new hidden printer capability flag support_cooling_filter
- "Use cooling filter" toggle in the Accessory group, shown only when
  the printer supports it; the air-filtration toggle hides in that case
  (no vendor restriction: third-party printers keep air filtration)
- explicit defaults (0) in the common machine base
- H2C declares support_cooling_filter=1 instead of support_air_filtration;
  its start-gcode already carries the cooling-filter conditional, so the
  toggle is functional. On H2C this drops the two exhaust-fan lines that
  air filtration emitted for ABS-class filaments, matching the printer's
  actual duct accessory; H2C is new on this branch so no existing user
  output changes.

Printers without the flag keep exactly the previous accessory UI and
g-code.

resources/profiles/BBL/machine/Bambu Lab H2C 0.4 nozzle.json

@@ -118,7 +118,7 @@
 		"14"
 	],
 	"support_chamber_temp_control": "1",
-	"support_air_filtration": "1",
+	"support_cooling_filter": "1",
 	"wrapping_exclude_area": [
 		"145x310",
 		"251x310",

resources/profiles/BBL/machine/fdm_machine_common.json

@@ -140,6 +140,8 @@
 	"silent_mode": "0",
 	"single_extruder_multi_material": "1",
 	"support_air_filtration": "0",
+	"support_cooling_filter": "0",
+	"cooling_filter_enabled": "0",
 	"support_chamber_temp_control": "0",
 	"support_fast_purge_mode": "0",
 	"support_object_skip_flush": "0",

src/libslic3r/Preset.cpp

@@ -1390,7 +1390,7 @@ static std::vector<std::string> s_Preset_printer_options {
     "default_print_profile", "inherits",
     "silent_mode",
     "scan_first_layer", "enable_power_loss_recovery", "wrapping_detection_layers", "wrapping_exclude_area", "machine_load_filament_time", "machine_unload_filament_time", "machine_tool_change_time", "time_cost", "machine_pause_gcode", "template_custom_gcode",
-    "nozzle_type", "nozzle_hrc","auxiliary_fan", "fan_direction", "nozzle_volume","upward_compatible_machine", "z_hop_types", "travel_slope", "retract_lift_enforce","support_chamber_temp_control","support_air_filtration","cooling_filter_enabled","printer_structure","farthest_point_timelapse",
+    "nozzle_type", "nozzle_hrc","auxiliary_fan", "fan_direction", "nozzle_volume","upward_compatible_machine", "z_hop_types", "travel_slope", "retract_lift_enforce","support_chamber_temp_control","support_air_filtration","support_cooling_filter","cooling_filter_enabled","printer_structure","farthest_point_timelapse",
     "best_object_pos", "head_wrap_detect_zone",
     "host_type", "print_host", "printhost_apikey", "flashforge_serial_number", "bbl_use_printhost", "printer_agent",
     "print_host_webui",

src/libslic3r/PrintConfig.cpp

@@ -4095,6 +4095,11 @@ void PrintConfigDef::init_fff_params()
     def->mode=comDevelop;
     def->set_default_value(new ConfigOptionBool(true));
 
+    // Printer capability flag: switches the accessory UI between air filtration and the cooling filter.
+    def = this->add("support_cooling_filter", coBool);
+    def->mode    = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
     def = this->add("cooling_filter_enabled", coBool);
     def->label = L("Use cooling filter");
     def->tooltip = L("Enable this if printer support cooling filter");

src/libslic3r/PrintConfig.hpp

@@ -1503,6 +1503,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionBool,                auxiliary_fan))
     ((ConfigOptionEnum<FanDirection>,  fan_direction))
     ((ConfigOptionBool,                support_air_filtration))
+    ((ConfigOptionBool,                support_cooling_filter))
     ((ConfigOptionBool,                cooling_filter_enabled))
     ((ConfigOptionEnum<PrinterStructure>,printer_structure))
     ((ConfigOptionBool,                support_chamber_temp_control))

src/slic3r/GUI/Tab.cpp

@@ -4959,6 +4959,7 @@ void TabPrinter::build_fff()
         optgroup->append_single_option_line("fan_direction");
         optgroup->append_single_option_line("support_chamber_temp_control", "printer_basic_information_accessory#support-controlling-chamber-temperature");
         optgroup->append_single_option_line("support_air_filtration", "printer_basic_information_accessory#support-air-filtration");
+        optgroup->append_single_option_line("cooling_filter_enabled");
 
         auto edit_custom_gcode_fn = [this](const t_config_option_key& opt_key) { edit_custom_gcode(opt_key); };
 
@@ -5895,6 +5896,10 @@ void TabPrinter::toggle_options()
         toggle_line("parallel_printheads_count", support_parallel_printheads);
 
         toggle_line("fan_direction", m_config->opt_bool("auxiliary_fan"));
+
+        // The cooling filter and air filtration are alternative accessories: show only the one the printer supports.
+        toggle_line("support_air_filtration", !m_config->opt_bool("support_cooling_filter"));
+        toggle_line("cooling_filter_enabled", m_config->opt_bool("support_cooling_filter"));
     }