The extruder_id*2 offset in get_axis_max_feedrate/get_axis_max_acceleration
was cherry-picked from BambuStudio's per-nozzle limit system, which OrcaSlicer
never ported. Without that system the limit arrays only have 2 values
([0]=Normal, [1]=Stealth), so any extruder_id > 0 or the uninitialized
value (255) would overshoot the array and fall back to values.back(),
always returning stealth-mode limits and producing incorrect time estimates.
Revert to indexing by time mode only (matching v2.3.1 behavior) and simplify
the M201/M203 handlers to write only the two mode slots they actually use.
859f401df5