Expanded Forge build budgets

- Sandbox nested builds divide reserved workers across matrix lanes
- Sandbox nested JVM processor counts follow each lane worker budget
- Forge targets reserve eight workers and 16 GiB with two test forks

build.gradle

@@ -333,11 +333,16 @@ Provider<IrisModdedBuildService> matrixWorkers = gradle.sharedServices.registerI
     maxParallelUsages.set(matrixParallelism)
 }
 List<String> nestedBuildArguments = [gradle.startParameter.buildCacheEnabled ? '--build-cache' : '--no-build-cache']
-if (providers.gradleProperty('multiplexorSandbox').getOrElse('false').toBoolean()) {
+boolean multiplexorSandbox = providers.gradleProperty('multiplexorSandbox').getOrElse('false').toBoolean()
+int nestedWorkers = multiplexorSandbox
+    ? Math.max(1, gradle.startParameter.maxWorkerCount.intdiv(matrixParallelism))
+    : Math.min(2, gradle.startParameter.maxWorkerCount)
+int nestedProcessors = multiplexorSandbox ? nestedWorkers : 2
+if (multiplexorSandbox) {
     nestedBuildArguments.addAll(['--no-daemon', '-PmultiplexorSandbox=true'])
 }
 String nestedJvmArguments = providers.gradleProperty('org.gradle.jvmargs').getOrElse('') +
-    ' -XX:ActiveProcessorCount=2'
+    " -XX:ActiveProcessorCount=${nestedProcessors}"
 if (gradle.startParameter.rerunTasks) {
     nestedBuildArguments.add('--rerun-tasks')
 }
@@ -373,7 +378,7 @@ irisModTargets.each { String targetMinecraft, Map<String, Object> target ->
             javaRuntime.set((int) target.java)
             List<String> command = [rootProject.file(moddedWrapperScript).absolutePath, 'assemble', 'compileTestJava',
                     'verifyLoggingPolicy', 'verifyNativeClassBoundary', '--console=plain',
-                    "--max-workers=${Math.min(2, gradle.startParameter.maxWorkerCount)}",
+                    "--max-workers=${nestedWorkers}",
                     "-Dorg.gradle.jvmargs=${nestedJvmArguments.trim()}",
                     "-Dorg.gradle.daemon.registry.base=${rootProject.file(".gradle/iris-daemons/slot-${daemonSlot}").absolutePath}",
                     '-Dorg.gradle.daemon.idletimeout=3600000',