feat: Cards writings and balancing (M8)

web/js/engine/world.js

@@ -0,0 +1,18 @@
+// The world outside the country: a slow business cycle with occasional shocks (global
+// slumps, rare booms). It moves growth and inflation, so even a perfect budget meets
+// good and bad years. state.world.cycle is roughly -4 (deep global recession) to +4.
+
+import { clamp } from "./state.js";
+import { nextFloat, nextNoise } from "./rng.js";
+
+export function stepWorld(state, bal) {
+  const w = bal.world;
+  const s = state.world;
+  s.cycle -= s.cycle / w.tau;
+  s.cycle += nextNoise(state, w.noise);
+  if (nextFloat(state) < w.shockChancePerDay) {
+    const size = w.shock * (0.6 + 0.8 * nextFloat(state));
+    s.cycle += nextFloat(state) < w.boomShare ? size * 0.6 : -size;
+  }
+  s.cycle = clamp(s.cycle, -w.max, w.max);
+}