feat(save): persist story flags and node progress in v1

src/engine/__tests__/save.test.ts

@@ -58,6 +58,17 @@ describe('createSave()', () => {
     state.actionQueue.push('forage');
     expect(save.state.actionQueue).toEqual(['forage', 'forage']);
   });
+
+  it('snapshots story fields in the save payload', () => {
+    const state = sampleState();
+    state.storyFlags = { route_a: true };
+    state.currentStoryNodeId = 'route_a_beat';
+    state.seenStoryNodeIds = ['boot_intro', 'route_a_beat'];
+    const save = createSave(state, 1700);
+    expect(save.state.storyFlags).toEqual({ route_a: true });
+    expect(save.state.currentStoryNodeId).toBe('route_a_beat');
+    expect(save.state.seenStoryNodeIds).toHaveLength(2);
+  });
 });
 
 describe('serialize / deserialize round-trip', () => {

src/engine/save.ts

@@ -29,6 +29,9 @@ export const gameStateSchema = z.object({
   activeActionId: z.string().nullable(),
   actionElapsedMs: z.number().nonnegative(),
   actionQueue: z.array(z.string()).default([]),
+  storyFlags: z.record(z.string(), z.boolean()).default({}),
+  currentStoryNodeId: z.string().default(''),
+  seenStoryNodeIds: z.array(z.string()).default([]),
 });
 
 export const saveSchema = z.object({
@@ -49,6 +52,9 @@ export function createSave(state: GameState, now: number): SaveData {
       activeActionId: state.activeActionId,
       actionElapsedMs: state.actionElapsedMs,
       actionQueue: [...state.actionQueue],
+      storyFlags: { ...state.storyFlags },
+      currentStoryNodeId: state.currentStoryNodeId,
+      seenStoryNodeIds: [...state.seenStoryNodeIds],
     },
   };
 }