Add Legacy-style Book Binder

build.gradle

@@ -78,6 +78,9 @@ neoForge {
         // The gametest system is also enabled by default for other run configs under the /test command.
         gameTestServer {
             type = "gameTestServer"
+            // Keep generated test Ages separate from worlds used by the dev client/server.
+            gameDirectory = project.file(project.findProperty('gameTestRunDir')
+                    ?: layout.buildDirectory.dir('gametest-run').get().asFile)
             systemProperty 'neoforge.enabledGameTestNamespaces', project.mod_id
         }
 
@@ -116,6 +119,44 @@ neoForge {
     }
 }
 
+// GameTests generate Ages, so their dedicated world can grow quickly across runs.
+// Never auto-delete a caller-supplied gameTestRunDir or a normal dev world.
+long gameTestWorldLimitMiB = providers.gradleProperty('gameTestMaxWorldMiB').orElse('512').get().toLong()
+if (gameTestWorldLimitMiB <= 0) {
+    throw new GradleException('gameTestMaxWorldMiB must be a positive number')
+}
+boolean customGameTestRunDir = providers.gradleProperty('gameTestRunDir').isPresent()
+File dedicatedGameTestDir = layout.buildDirectory.dir('gametest-run').get().asFile.canonicalFile
+File dedicatedGameTestWorld = new File(dedicatedGameTestDir, 'world')
+def cleanOversizedGameTestWorld = tasks.register('cleanOversizedGameTestWorld') {
+    doLast {
+        if (customGameTestRunDir) {
+            getLogger().lifecycle('Skipping automatic GameTest world cleanup for custom gameTestRunDir')
+            return
+        }
+
+        def worldDir = dedicatedGameTestWorld
+        if (!worldDir.isDirectory() || java.nio.file.Files.isSymbolicLink(worldDir.toPath())) {
+            return
+        }
+
+        def paths = java.nio.file.Files.walk(worldDir.toPath()).withCloseable { it.toList() }
+        long bytes = paths.sum(0L) { path ->
+            java.nio.file.Files.isRegularFile(path, java.nio.file.LinkOption.NOFOLLOW_LINKS)
+                    ? java.nio.file.Files.size(path) : 0L
+        }
+        long limit = gameTestWorldLimitMiB * 1024L * 1024L
+        if (bytes > limit) {
+            getLogger().lifecycle('Removing oversized GameTest world {} ({} MiB; limit {} MiB)',
+                    worldDir, Math.ceil(bytes / 1048576d) as long, gameTestWorldLimitMiB)
+            paths.toSorted(java.util.Comparator.reverseOrder()).each { java.nio.file.Files.delete(it) }
+        }
+    }
+}
+tasks.named('runGameTestServer').configure {
+    dependsOn(cleanOversizedGameTestWorld)
+}
+
 // Sets up a dependency configuration called 'localRuntime'.
 // This configuration should be used instead of 'runtimeOnly' to declare
 // a dependency that will be present for runtime testing but that is