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.

panel/server/tests/api.rs

@@ -27,7 +27,7 @@ async fn admin_only_routes_are_guarded() {
     let admin = t.login("admin", "supersecret").await;
     let (s, v) = t.call("POST", "/api/admin/users", Some(&admin), Some(json!({"username": "Steve", "password": "password123"}))).await;
     assert_eq!(s, StatusCode::OK, "{v}");
-    assert_eq!(v["uuid"], scopenet_shared::offline_uuid("Steve"));
+    assert_eq!(uuid::Uuid::parse_str(v["uuid"].as_str().unwrap()).unwrap().get_version_num(), 4);
 
     let player = t.login("steve", "password123").await; // usernames are case-insensitive
     let (s, _) = t.call("GET", "/api/admin/users", Some(&player), None).await;