[WIP] feat(auth): add algorithm property to Signer base class

[ohmayr]

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Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Code Review

This pull request introduces an algorithm property to the base Signer class and its RSA implementations, and updates the JWT encoding logic to dynamically retrieve the algorithm from the signer using getattr. The review feedback points out a potential issue when signer is a mock object, as getattr(signer, "algorithm", None) would return a truthy mock object and bypass the fallback to "RS256". It suggests explicitly checking if the retrieved algorithm is a string.