Fix CLI multi-color slicing crash for single-extruder AMS printers (P1S/P1P/X1C)

[ryanhebert]

Summary

Fixes ACCESS_VIOLATION crash in CLI multi-color slicing when using --load-assemble-list with single-extruder AMS printers.

Changes

Three fixes in src/libslic3r/PrintConfig.cpp:

1. Null check for filament_map (line 8460): printer_config.option<ConfigOptionInts>("filament_map") returns null in CLI mode since filament_map is initialized by the GUI workflow. Added null check with early return.

2. Null checks for extruder_type and nozzle_volume_type (lines 8465-8466): dynamic_cast returns null when these options aren't present in standalone profile files. Added null check with early return.

3. Bounds clamping on get_at() calls (lines 8478-8479, 8265): filament_maps contains AMS slot numbers (e.g., [3, 4, 1]) used as indices into extruder_type/nozzle_volume_type arrays that typically have only 1-2 entries. get_at(3) on a 2-element array → out-of-bounds → crash. Fixed with std::clamp().

Root Cause

For single-extruder AMS printers (P1S, P1P, X1C), support_different_extruders() returns true due to extruder_variant_list: ["Direct Drive Standard", "Direct Drive High Flow"]. This triggers the multi-extruder code path in update_values_to_printer_extruders_for_multiple_filaments(), which accesses fields that are either uninitialized (CLI mode) or have fewer entries than the filament map indices expect.

Testing

CLI command that crashes before fix:

bambu-studio --load-assemble-list assemble.json \
  --load-settings "machine.json;process.json" \
  --load-filaments "filament.json;..." \
  --slice 0 --export-3mf sliced.3mf

Crash trace:

update_filament_maps_to_config: filament maps changed after pre-slicing.
update_values_to_printer_extruders_for_multiple_filaments, Line 8449: different nozzle volume processing
[ACCESS VIOLATION - exit code -1073741819]

Fixes #10465

Note: Same fix submitted to OrcaSlicer at OrcaSlicer/OrcaSlicer#13406