fix: port BBS NozzleStatusRecorder pattern for per-carousel-slot purge tracking

The upstream _make_wipe_tower() tracked purge volumes per-extruder (2 slots),
which collapsed all H2C carousel filaments into one slot and caused massive
redundant AMS flushing (~40g instead of ~0.4g).

Changes:
- Print.cpp: Replace per-extruder nozzle_cur_filament_ids with BBS
  NozzleStatusRecorder that tracks per group_id (carousel slot 0..6).
  Use get_nozzle_for_filament() to resolve physical slot per layer.
  Select filament_prime_volume_nc for nozzle changes, filament_prime_volume
  for filament changes (BBS pattern).
- PrintConfig.hpp/cpp: Register filament_prime_volume (per-filament EC prime
  volume, default 45mm³) matching BBS PrintConfig.
- Preset.cpp: Add filament_prime_volume to preset keys list.

Safe for non-carousel printers: group_id == extruder_id when each extruder
has one nozzle, so NozzleStatusRecorder behaves identically to the original
per-extruder tracking.

Reference to BBS: BambuStudio/src/libslic3r/Print.cpp _make_wipe_tower() L3341-3392

src/libslic3r/PrintConfig.cpp

@@ -7995,6 +7995,15 @@ void PrintConfigDef::init_fff_params()
     def->mode = comDevelop;
     def->set_default_value(new ConfigOptionBool(false));
 
+    // Reference to BBS: BambuStudio/src/libslic3r/PrintConfig.cpp L2617-2624
+    def           = this->add("filament_prime_volume", coFloats);
+    def->label    = L("Filament change");
+    def->tooltip  = L("The volume of material required to prime the extruder on the tower, excluding a hotend change.");
+    def->sidetext = L("mm³");
+    def->min      = 1.0;
+    def->mode     = comSimple;
+    def->set_default_value(new ConfigOptionFloats{45.});
+
     def           = this->add("filament_prime_volume_nc", coFloats);
     def->label    = L("Hotend change");
     def->tooltip  = L("The volume of material required to prime the extruder for a hotend change on the tower.");