Fix summaries to add percent colored by category

The `Legend` class should compute percentages colored by each category and show as part of the summary.

Start by locating the Legend class and its summary-generation code. Trace how categories are represented and how summary values are currently computed, then verify that each category's percentage is shown with its corresponding color. Done means the summary displays category-colored percentages without changing unrelated legend behavior.

Written by the indexing model from the issue text.