Complete private authentication, server integrations and activity reporting

Add Fabric/Forge version builds and Paper integration, preserve permanent player identities across renames, harden session authorization, and surface privacy-conscious launcher/server activity in the panel.

integrations/build.gradle

@@ -0,0 +1,12 @@
+allprojects {
+    group = 'net.scopenet'
+    version = providers.gradleProperty('releaseVersion').getOrElse('0.1.0')
+    repositories { mavenCentral() }
+}
+subprojects {
+    apply plugin: 'java'
+    java.sourceCompatibility = JavaVersion.VERSION_17
+    java.targetCompatibility = JavaVersion.VERSION_17
+    tasks.withType(JavaCompile).configureEach { options.encoding = 'UTF-8' }
+    tasks.withType(Test).configureEach { useJUnitPlatform() }
+}