principle-migrate-callers-then-delete-legacy-apis

Guides coordinated internal API refactors so callers move to the new contract without leaving compatibility layers behind.

When to use it

Use when introducing an internal API during simplification or refactoring, provided no external users need backward compatibility and the project can absorb coordinated breaking changes.

It changes how the agent refactors internal APIs by migrating callers, removing the old API, and updating tests to assert the new contract.