fix: apply smart preview defaults per extruder count session
- Track last extruder count (1=single, 2+=multi) instead of boolean flag
- Apply appropriate default (ColorPrint/FeatureType) when count changes
- User selections persist within same extruder count
- Symmetric behavior: both single and multi actively apply defaults
- Delete duplicate dead code block (uncommented TODO scaffolding)
Behavior:
- First slice (any type) → appropriate default
- User changes view → persists on re-slice
- Switch single→single or multi→multi → persists
- Switch single↔multi → appropriate default applies
fix(printconfig): register enable_filament_dynamic_map and has_filament_switcher options
PR #13388 (X2D Support) added import/export for these options in
bbs_3mf.cpp but never registered them in PrintConfig.cpp. Loading any
.3mf containing these keys throws UnknownOptionException at
PartPlate.cpp:6153 when config->apply() looks up the missing definition.
Allyn Malventano