chore: bump version to 0.4.0, add Gradle 9.6 wrapper, and finalize builds for NSIS, Docker, Fabric, Forge, and Paper

integrations/fabric/modern.gradle

@@ -1,5 +1,5 @@
 plugins { id 'net.fabricmc.fabric-loom' version '1.17.17' }
-def mc = providers.gradleProperty('mcVersion').get()
+def mc = (providers.gradleProperty('mcVersion').orNull ?: project.findProperty('mcVersion') ?: '26.1.2').toString().trim()
 if (providers.gradleProperty('verifyMixins').isPresent()) {
     loom { runs { server { vmArg '-Dscopenet.verifyMixins=true' } } }
 }