Three bugs on the same PLA-model + PVA-support flow, discovered in
sequence:
(A) substitute_unused_plate_filaments inspected only object geometry
(per-object extruder metadata + paint_color triangles) so a support-
only slot was silently treated as "unused" and the user's PVA profile
got overwritten with slot 1's PLA.
(B) _extract_filament_info stripped filament_is_support==1 entries,
hiding PVA from unsliced source archive cards even when the project
explicitly configured it.
(C) --load-settings is authoritative over the source's project_settings.
config, and Bambu's shipped process presets ship enable_support=0
(supports are a per-print decision, not per-quality). So even with
(A) fixed, the sliced output had supports disabled and the PVA slot
loaded but never consumed. Inverts BambuStudio GUI's semantics where
the project overrides the preset.
Fixes:
- New extract_support_filament_slots_from_3mf reads enable_support +
support_filament + support_interface_filament from project_settings.
config; substitute_unused_plate_filaments unions it into the geometry-
derived set.
- _extract_filament_info returns all configured filament types + colours.
- New _patch_process_support_settings overlays four fields (enable_
support, support_filament, support_interface_filament, support_type)
from the source 3MF onto the picked process preset JSON before
--load-settings sees it. Deliberately targeted to what fixes#1881
without widening to a full project-over-preset merge.
