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/common/build.gradle

@@ -0,0 +1,5 @@
+dependencies {
+    implementation 'com.google.code.gson:gson:2.10.1'
+    testImplementation 'org.junit.jupiter:junit-jupiter:5.11.4'
+    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
+}