Complete milestone 3 book previews and Age generators

build.gradle

@@ -33,6 +33,10 @@ repositories {
         content { includeGroup 'curse.maven' }
     }
     maven { url = 'https://maven.bai.lol' }
+    maven {
+        url = 'https://api.modrinth.com/maven'
+        content { includeGroup 'maven.modrinth' }
+    }
 }
 
 base {
@@ -121,7 +125,10 @@ configurations {
 }
 
 dependencies {
-    implementation "net.createmod.ponder:ponder-neoforge:${ponder_version}+mc${minecraft_version}"
+    // Create bundles the Ponder APIs used by the optional snapshot preview.
+    // Keep them on the compile classpath without forcing either mod at runtime.
+    compileOnly "net.createmod.ponder:ponder-neoforge:${ponder_version}+mc${minecraft_version}"
+    compileOnly "maven.modrinth:immersive-portals-neoforge:${immersive_portals_version}"
     implementation "curse.maven:dynamicdimension-ar-edition-1469680:${dynamic_dimensions_file_id}"
     implementation "lol.bai:badpackets:neo-${badpackets_version}"
     // Example optional mod dependency with JEI