Imports
Section 21.4 - Analysis of union by rank with path compression (legacy
compatibility path)
Third-edition-numbered compatibility path for the union-find analysis.
The canonical fourth-edition source is
CLRSLean.FourthEdition.Chapter_19.Section_19_4_Analysis;
this module forwards to it so legacy imports keep working during the
compatibility period (see docs/migrations/clrs4.md).