Refactor Logon and Logoff Services

[pheller]

• They were becoming very difficult to reason through and the use of the with construct felt forced.
• Introduced a railway oriented approach to the processing pipeline - and_then will handle either invoking succeeding pipeline steps - perhaps adding to the pipeline context, or just pass errors through, letting the final step construct an appropriate response

[Copilot]

Pull Request Overview

This PR refactors the Logon and Logoff services to use a railway-oriented programming approach, replacing the previous with construct with an and_then pipeline pattern for better code clarity and error handling.

• Introduces railway-oriented programming with and_then combinators for linear processing pipelines
• Breaks down complex monolithic functions into smaller, focused pipeline stages
• Consolidates error handling and response building logic

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
apps/server/lib/prodigy/server/service/logon.ex	Complete refactor using railway pattern with pipeline stages for parsing, validation, authentication, and session management
apps/server/lib/prodigy/server/service/logoff.ex	Refactored to use railway pattern with improved error handling and cleaner separation of concerns

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