feat: port monthly scout policy actions

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

@@ -0,0 +1,41 @@
+import type { InMemoryTurnWorld } from './inMemoryWorld.js';
+import type { MonthlyEventActionHandler } from './monthlyEventHandler.js';
+
+const readOptionalBlockFlag = (value: unknown, actionName: string): boolean | null => {
+    if (value === undefined || value === null) {
+        return null;
+    }
+    if (typeof value !== 'boolean') {
+        throw new Error(`${actionName} blockChangeScout must be a boolean or null.`);
+    }
+    return value;
+};
+
+export const createScoutBlockHandler = (options: {
+    actionName: 'BlockScoutAction' | 'UnblockScoutAction';
+    getWorld: () => InMemoryTurnWorld | null;
+}): MonthlyEventActionHandler => {
+    return (args) => {
+        const world = options.getWorld();
+        if (!world) {
+            return;
+        }
+        if (options.actionName === 'UnblockScoutAction') {
+            // ref omits MeekroDB's required WHERE argument and fails before
+            // changing nation or game state. No provided scenario invokes it.
+            throw new Error('update(): at least 3 arguments expected');
+        }
+        for (const nation of world.listNations()) {
+            world.updateNation(nation.id, {
+                meta: {
+                    ...nation.meta,
+                    scout: 1,
+                },
+            });
+        }
+        const blockChangeScout = readOptionalBlockFlag(args[0], options.actionName);
+        if (blockChangeScout !== null) {
+            world.updateWorldMeta({ block_change_scout: blockChangeScout });
+        }
+    };
+};