#13806 Python: Add category mapping API for discrete properties

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

GrpcInterface/Python/rips/PythonExamples/case_and_grid_operations/set_discrete_active_cell_property.py

@@ -0,0 +1,28 @@
+######################################################################
+# This script creates a discrete (integer) property for all active
+# cells in the first case in the project.
+#
+# Passing data_type="INTEGER" flags the property as discrete regardless
+# of the property name (previously this required the name to end with
+# "NUM").
+######################################################################
+import rips
+
+resinsight = rips.Instance.find()
+
+case = resinsight.project.case(case_id=0)
+
+# Derive a discrete region id from a continuous property.
+poro = case.active_cell_property("STATIC_NATIVE", "PORO", 0)
+region_ids = [int(value * 100) % 4 for value in poro]
+
+print("Applying discrete values to active cells")
+case.set_active_cell_property(
+    region_ids, "GENERATED", "MY_REGION", 0, data_type="INTEGER"
+)
+
+# Bind integer values to text labels so the legend shows names instead of numbers.
+case.set_discrete_property_category_names(
+    property_name="MY_REGION",
+    value_names={0: "Sand", 1: "Shale", 2: "Coal", 3: "Limestone"},
+)

GrpcInterface/Python/rips/PythonExamples/case_and_grid_operations/set_discrete_grid_property.py

@@ -0,0 +1,33 @@
+######################################################################
+# This script creates a discrete (integer) grid property for all grid
+# cells in the first case in the project.
+#
+# A discrete property is visualized with a category legend, in contrast
+# to the continuous legend used for floating point properties. Passing
+# data_type="INTEGER" flags the property as discrete regardless of the
+# property name (previously this required the name to end with "NUM").
+######################################################################
+import rips
+
+resinsight = rips.Instance.find()
+
+case = resinsight.project.case(case_id=0)
+grid = case.grid()
+grid_cell_count = grid.cell_count()
+print("total cell count : " + str(grid_cell_count))
+
+# Assign a simple region id based on IJK index.
+values = []
+for i in range(0, grid_cell_count):
+    values.append(i % 4)
+
+print("Applying discrete values to main grid")
+case.set_grid_property(values, "STATIC_NATIVE", "MY_REGION", 0, data_type="INTEGER")
+
+# Bind integer values to text labels so the legend shows names instead of numbers.
+# Colors are optional — values without a color get an auto-assigned palette color.
+case.set_discrete_property_category_names(
+    property_name="MY_REGION",
+    value_names={0: "Sand", 1: "Shale", 2: "Coal", 3: "Limestone"},
+    value_colors={0: "#e6c878", 1: "#646464"},
+)