feat(engine): execute story actions via storyChoiceId

src/engine/game.ts

@@ -1,4 +1,8 @@
 import type { Content } from '../content/schema';
+import type { StoryContent } from '../content/storySchema';
+import { applyChoice, isStoryChoiceAvailable } from './story';
+
+type GameContent = Content & StoryContent;
 
 /**
  * Core game state and per-tick simulation.
@@ -173,6 +177,26 @@ export function executeInstant(state: GameState, content: Content, actionId: str
   grantYields(state, content, actionId);
 }
 
+/**
+ * Execute a story action by resolving its storyChoiceId and applying it.
+ * Throws if the action is not of kind 'story', has no storyChoiceId, or the
+ * choice is not currently available.
+ */
+export function executeStoryAction(
+  state: GameState,
+  content: GameContent,
+  actionId: string,
+): void {
+  const action = content.actionsById[actionId];
+  if (!action || action.kind !== 'story' || !action.storyChoiceId) {
+    throw new Error(`Action "${actionId}" is not a story action`);
+  }
+  if (!isStoryChoiceAvailable(state, content, action.storyChoiceId)) {
+    throw new Error(`Story choice "${action.storyChoiceId}" is not available`);
+  }
+  applyChoice(state, content, action.storyChoiceId);
+}
+
 /**
  * Advance the active action by `tickMs`. On completion, grants yields and
  * advances the queue — actions do not auto-repeat when the queue is empty.