chore: pass PR1 verification gate (format, lint, coverage)

src/engine/game.ts

@@ -99,7 +99,10 @@ function beginAction(state: GameState, content: Content, actionId: string): void
 
 function startNextFromQueue(state: GameState, content: Content): void {
   while (state.actionQueue.length > 0) {
-    const nextId = state.actionQueue.shift()!;
+    const nextId = state.actionQueue.shift();
+    if (!nextId) {
+      break;
+    }
     if (isActionAvailable(state, content, nextId)) {
       beginAction(state, content, nextId);
       return;