Add -Ysafe-init compiler option

https://docs.scala-lang.org/scala3/reference/other-new-features/safe-initialization.html

build.sbt

@@ -16,7 +16,7 @@ lazy val app = project
   .settings(
     name         := "lila-fishnet",
     organization := "org.lichess",
-    scalacOptions ++= Seq("-source:future", "-rewrite", "-indent", "-explain", "-Wunused:all", "-release:21"),
+    scalacOptions ++= Seq("-source:future", "-rewrite", "-indent", "-explain", "-Wunused:all", "-release:21", "-Ysafe-init"),
     resolvers ++= Seq(Dependencies.lilaMaven),
     libraryDependencies ++= Seq(
       catsCore,