refactor(es_extended/server/class/player): add proper type annotations

[Kenshiin13]

Description

This PR adds proper type annotations for the xPlayer class, including all properties and methods. Each function now has clearly defined parameter and return types, improving type safety and editor autocomplete support for developers using the class.

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Motivation

Adding type annotations helps prevent runtime errors, improves code readability, and provides better support for IDEs with type checking and IntelliSense. This change directly resulted in multiple warnings in the codebase which would have resulted in unexpected behaviour or errors.

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PR Checklist

• My commit messages and PR title follow the Conventional Commits standard.
• My changes have been tested locally and function as expected.
• My PR does not introduce any breaking changes.
• I have provided a clear explanation of what my PR does, including the reasoning behind the changes and any relevant context.

[Zykem]

LGTM