Gate JEI mixin behind mod presence check to prevent crashes without JEI

[Copilot]

The jei.RecipeRegistryMixin was unconditionally loaded in the client mixin set, causing crashes when JEI is not installed (JEI is declared as an optional dependency via after:jei).

Changes

• Created GregTechEnergisticsMixinPlugin: Implements IMixinConfigPlugin to conditionally load mixins based on Loader.isModLoaded("jei")
• Updated mixin config: Added plugin reference to mixins.gregtechenergistics.json
• Convention: JEI-specific mixins in the .jei subpackage are gated; all other mixins load unconditionally

@Override
public boolean shouldApplyMixin(String targetClassName, String mixinClassName) {
    String jeiMixinPackage = mixinPackage + JEI_PACKAGE_SUFFIX;
    if (mixinClassName.startsWith(jeiMixinPackage)) {
        return Loader.isModLoaded(JEI_MOD_ID);
    }
    return true;
}

The plugin derives the JEI package dynamically from the mixinPackage parameter, making it resilient to package refactoring.

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• nexus.gtnewhorizons.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED -Xmx5G -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.9-bin/90cnw93cvbtalezasaz0blq0a/gradle-8.9/lib/gradle-daemon-main-8.9.jar -javaagent:/home/REDACTED/.gradle/wrapper/dists/gradle-8.9-bin/90cnw93cvbtalezasaz0blq0a/gradle-8.9/lib/agents/gradle-instrumentation-agent-8.9.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.9 (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)