Introduce set_discrete_property_category_names on Case to bind integer
result values to text labels and optional colors. Internally it creates a
custom ColorLegend, appends one item per value (with an auto-assigned
palette color when the caller does not provide one) and registers the
legend as the default for the (case, resultName) pair.
Also add Project.color_legend_collection() as a dedicated accessor for
the project's ColorLegendCollection, pytest coverage for legend creation
and the default-legend-for-result binding, and two PythonExamples
demonstrating the end-to-end discrete property + category label flow.
#13806 Python: Silence mypy warnings for category_mapping module
Magne Sjaastad
03409aed70