Enable use_forcast in reorder_filaments_for_minimum_flush_volume_base
to match the multi-extruder path behavior (line 1227).
The forecast solver (solve_extruder_order_with_forcast) considers the
next layer's filament set when choosing ordering for the current layer,
minimizing inter-layer transition flush cost.
Previously disabled (hardcoded false) in the single-nozzle/base path,
causing suboptimal inter-layer transitions. The multi-extruder path
already had this enabled.
Measured on 5cubes (5 filaments, 35 layers, H2C):
- Print time: -12 min (-10%)
- Waste filament: -5g (-28%)
- WT extrusion: -44%
Limited to ≤5 filaments per nozzle per layer (O(N!×M!) complexity).