Add Sorbet type annotations to UpdateChecker, LatestVersionFinder, and VersionResolver for npm_and_yarn

[kbukum1]

What are you trying to accomplish?

This PR introduces Sorbet type annotations to three core classes in the npm_and_yarn ecosystem:

• UpdateChecker
• LatestVersionFinder
• RegistryFinder
• VersionResolver

What:
The goal is to improve static type safety and developer tooling support for these critical components of the npm/yarn update logic. Types have been added to method signatures, internal state, and helper methods where appropriate.

Why:
Adding Sorbet types to these classes increases confidence when making future changes, helps catch bugs earlier, and makes the code easier to navigate for contributors unfamiliar with the implicit contracts in these classes.

Anything you want to highlight for special attention from reviewers?

How will you know you've accomplished your goal?

• The code now passes srb tc with no type errors on the updated files.
• The classes still pass all tests, ensuring functional equivalence.
• Contributors working on these classes will now benefit from typed method signatures and IDE/autocomplete support.

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.