Add refactoring change manager compatibility hook

[Gabriel-Darbord]

Summary

• Add PharoCompatibility refactoringChangeManagerClass as a Pharo 13 surface hook.
• Answer RBRefactoryChangeManager directly on Pharo 12/13 runtimes and ReChangeManager directly on Pharo 14.
• Add focused runtime-specific contract tests for the hook.

Verification

• P13: PharoCompatibilityP13SurfacePharo13Test
• P14: PharoCompatibilityP13SurfacePharo14Test>>testRefactoringChangeManagerClass
• P12: PharoCompatibilityP13SurfacePharo12Test>>testRefactoringChangeManagerClass
• git diff --check

Related

• Required by Avoid job-backed method rewrite application MCP#56 to avoid version probing inside MCP.