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/libslic3r/Print.hpp

@@ -1005,7 +1005,7 @@ public:
     const WipeTowerData&        wipe_tower_data(size_t filaments_cnt = 0) const;
     const ToolOrdering& 		tool_ordering() const { return m_tool_ordering; }
 
-    void update_filament_maps_to_config(std::vector<int> f_maps);
+    void update_filament_maps_to_config(std::vector<int> f_maps, std::vector<int> f_volume_maps = std::vector<int>{}, std::vector<int> f_nozzle_maps = std::vector<int>{});
     void apply_config_for_render(const DynamicConfig &config);
 
     // 1 based group ids