Imports
Section 29.4 - Duality (legacy compatibility path)
Third-edition-numbered compatibility path for the duality development
(fourth-edition Section 29.3). The canonical fourth-edition source is
CLRSLean.FourthEdition.Chapter_29.Section_29_3_Duality;
this module forwards to it so legacy imports keep working during the
compatibility period (see docs/migrations/clrs4.md).