Rework story engine flow and reorganize project docs

src/services/storyEngine/saveMigrationManifest.ts

@@ -0,0 +1,36 @@
+import type {
+  GameState,
+  SaveMigrationManifest,
+} from '../../types';
+import { createEmptyStoryEngineMemoryState } from './visibilityEngine';
+
+export function buildSaveMigrationManifest(params: {
+  version: string;
+}) {
+  return {
+    version: params.version,
+    requiredTransforms: [
+      'ensure_story_engine_memory',
+      'ensure_campaign_state',
+      'ensure_player_style_profile',
+    ],
+    backwardCompatible: true,
+  } satisfies SaveMigrationManifest;
+}
+
+export function applyStoryEngineMigration(params: {
+  state: GameState;
+  manifest: SaveMigrationManifest;
+}) {
+  const storyEngineMemory =
+    params.state.storyEngineMemory ?? createEmptyStoryEngineMemoryState();
+
+  return {
+    ...params.state,
+    storyEngineMemory: {
+      ...createEmptyStoryEngineMemoryState(),
+      ...storyEngineMemory,
+      saveMigrationManifest: params.manifest,
+    },
+  };
+}