fix staged nation tax rate consumption

app/game-engine/src/turn/nationTaxRate.ts

@@ -0,0 +1,11 @@
+import { asNumber } from '@sammo-ts/common';
+
+const DEFAULT_NATION_RATE = 20;
+
+export const resolveAppliedNationRate = (meta: Record<string, unknown>): number => {
+    const stagedRate = meta.rate_tmp;
+    if (typeof stagedRate === 'number' && Number.isFinite(stagedRate)) {
+        return stagedRate;
+    }
+    return asNumber(meta.rate, DEFAULT_NATION_RATE);
+};