public/js/render/fx.js becomes a re-export barrel. Speeds, camera heights, fonts, the kind table and the shared tunables move verbatim into public/js/render/fx/*.js. FxSystem keeps its constructor, clear, update, counts and destroy; the other methods move verbatim into container classes installed on FxSystem.prototype in source order. simSpeeds and fontsReady each stay one instance. The dynamic import of /sim/constants.js stays next to setSimProjectileSpeeds.