Imports

CLRS fourth edition

This is the canonical chapter tree for CLRS-Lean. During the compatibility period the guides reuse theorem-bearing modules whose paths follow the third edition. New work should start from a CLRSLean.FourthEdition.Chapter_NN guide and consult docs/clrs-fourth-edition-map.csv before choosing a section module.

The FourthEdition prefix is transitional. At the cleanup major release, unqualified CLRSLean.Chapter_NN paths will adopt fourth-edition meanings.