AbstractStaticcreateFactory method for creating trace instances.
This method is intentionally kept lightweight and only receives
trace-local data (layer) plus minimal plot-level hints via options.
It must not receive or inspect the full layers array to keep
construction decoupled from subplot-wide state.
Optionaloptions: { isViolinPlot?: boolean }OptionalisViolinPlot?: booleanHint that this subplot structurally represents a violin plot, i.e. it contains both BOX and SMOOTH layers.
The detection of this condition is performed by the caller
(e.g. Subplot), not by the factory itself.
Abstract factory class for creating appropriate trace instances based on layer type.