Preserve runtime final annotations in compiled core modules

[cofin]

Summary

Core modules should use runtime-safe Final annotations so interpreted and compiled executions agree on type metadata while avoiding compatibility issues in compiled classes.

Scope

• Keep Final annotations available at runtime where tests and tooling inspect them.
• Preserve compiled-module compatibility across cache, compiler, parameter, result, and stack helpers.
• Avoid behavioral changes to public APIs.

Validation

Covered by compiler/result unit tests and type checks in PR #545.