Updated Iris packaging

- Version is 4.1.2-26.2 across platform builds
- Plugin builds use shared automatic jar selection
- Native adapters remain bundled in selected artifacts
- Plugin export tasks copy the selected artifact
- The previous plugin packer is removed
- The agent tracks primary storage closure during Spigot shutdown

gradle/packed-jar.gradle

@@ -1,59 +0,0 @@
-import org.gradle.api.tasks.compile.JavaCompile
-import org.gradle.api.artifacts.component.ComponentIdentifier
-
-configurations {
-    packedXz
-}
-
-dependencies {
-    packedXz('org.tukaani:xz:1.10')
-}
-
-def originalJar = tasks.named('jar', Jar)
-sourceSets {
-    packedBootstrap {
-        java.srcDir('packaging/xz/src/main/java')
-        compileClasspath = files(originalJar.flatMap { it.archiveFile }) + configurations.packedXz
-    }
-    packedBootstrapTest {
-        java.srcDir('packaging/xz/src/test/java')
-        compileClasspath += sourceSets.packedBootstrap.output + sourceSets.packedBootstrap.compileClasspath
-        runtimeClasspath += sourceSets.packedBootstrap.output + sourceSets.packedBootstrap.compileClasspath
-    }
-}
-
-dependencies {
-    packedBootstrapTestImplementation('junit:junit:4.13.2')
-}
-
-tasks.named('compilePackedBootstrapJava', JavaCompile).configure {
-    dependsOn(originalJar)
-}
-
-tasks.register('packedBootstrapTest', Test) {
-    group = 'verification'
-    testClassesDirs = sourceSets.packedBootstrapTest.output.classesDirs
-    classpath = sourceSets.packedBootstrapTest.runtimeClasspath
-}
-
-tasks.register('packedJar', PackedJar) {
-    group = 'build'
-    description = 'Builds a Bukkit jar with an embedded XZ runtime payload.'
-    dependsOn(tasks.named('verifyBukkitArtifact'), tasks.named('packedBootstrapClasses'), configurations.nativeRuntime)
-    inputJar.set(originalJar.flatMap { it.archiveFile })
-    bootstrapClasses.from(sourceSets.packedBootstrap.output.classesDirs)
-    decoderJars.from(configurations.packedXz)
-    nativeArtifacts.set(providers.provider {
-        Map<ComponentIdentifier, File> resolved = new LinkedHashMap<>()
-        configurations.nativeRuntime.incoming.artifacts.artifacts.each { artifact ->
-            resolved.put(artifact.id.componentIdentifier, artifact.file)
-        }
-        PackedJar.resolveNativeArtifacts(resolved)
-    })
-    outputJar.set(layout.buildDirectory.file(originalJar.flatMap { it.archiveFileName }
-        .map { String name -> "libs/${name.replaceFirst(/\.jar$/, '-xz.jar')}" }))
-}
-
-tasks.named('check').configure {
-    dependsOn(tasks.named('packedBootstrapTest'))
-}