Review cut_* functions for standard colours and categories

Some of the colours chosen are design choices we have made for our specific reporting requirements but are not mandated by caaqs. Should probably pull these out or generalize them so other people can make their own design choices.

Start by locating the cut_* functions and reading how they currently assign colours and categories. Compare those choices with the reporting requirements described in the issue, then define what generalized or configurable behavior would count as complete; the issue does not name specific files or tests.

Written by the indexing model from the issue text.