Migrate FightSystem modes and countdowns to GameCore

- Move shared arena-mode abstractions into GameCore
- Adapt fight countdowns and APIs to the shared model
- Add SteamWar issue audit workflow and SQL language settings

FightSystem/build.gradle.kts

@@ -30,6 +30,11 @@ dependencies {
     implementation(project(":FightSystem:FightSystem_Core"))
 }
 
+tasks.withType<FightServer>().configureEach {
+    dependsOn(":KotlinCore:shadowJar")
+    dependsOn(":GameCore:jar")
+}
+
 tasks.register<FightServer>("HalloweenWS") {
     group = "run"
     description = "Run a Halloween 1.21 Fight Replay Server"