Creates a new SymbolRecognition instance.
Does not load the model — call load first.
Model URL and confidence threshold.
Loads and initialises the classifier model from the configured URL.
Resolves when the model is ready to classify.
Classifies a stroke group into a symbol label.
The StrokeGroup to classify.
Lookup map from stroke ID to Stroke data.
The classification result including label and confidence.
Classifies stroke groups into mathematical symbol labels.