Fix Java compilation warnings

[demoth]

Summary

• replace deprecated wrapper constructors with valueOf in Vargs
• remove deprecated Integer constructors in rendering and audio code
• simplify player list lookup in game exports

Testing

• ./gradlew build -x test
• ./gradlew test

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https://chatgpt.com/codex/tasks/task_e_6854526d63cc8329932a0f275623c750

[Copilot]

Pull Request Overview

This PR fixes Java compilation warnings by replacing deprecated wrapper constructors with their corresponding valueOf methods and simplifying the player list lookup logic.

• Replaced deprecated Boolean, Byte, Character, Short, Integer, Long, Float, and Double constructors in Vargs.
• Updated similar constructor calls in GameExportsImpl, Channel, and Model.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
qcommon/src/main/java/jake2/qcommon/util/Vargs.java	Replaced wrapper constructors with valueOf calls.
game/src/main/java/jake2/game/GameExportsImpl.java	Replaced constructor usage in player lookup with valueOf.
client/src/main/java/jake2/client/sound/lwjgl/Channel.java	Replaced deprecated Integer constructor with valueOf for key.
client/src/main/java/jake2/client/render/fast/Model.java	Replaced deprecated Integer constructor with valueOf for tmp.