feat(satisfactory): mark the server ready on 'Engine is initialized'

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MZxvxViV6QwAtVWT3saGvs

games/satisfactory-vanilla-stable/test.yaml

@@ -2,3 +2,4 @@
 # Values CI uses to boot-test this game. Never put real credentials here: map them under 'secrets'.
 # SteamCMD install of ~8 GB plus first start
 timeoutSec: 2400
+readyExample: "LogInit: Display: Engine is initialized. Leaving FEngineLoop::Init()"