feat: emit app state snapshots on all mutating workflows

test/app.test.js

@@ -5,7 +5,7 @@ const assert = require("node:assert/strict");
 const { buildApp } = require("../src/app");
 const { hmacSHA256Hex } = require("../src/lib/signature");
 
-function createApp() {
+function createApp(options = {}) {
   return buildApp({
     config: {
       xWebhookSecret: "x-secret",
@@ -18,6 +18,7 @@ function createApp() {
         maxCharsPerArticle: 120000,
       },
     },
+    ...options,
   });
 }
 
@@ -194,3 +195,32 @@ test("X webhook valid flow processes article", () => {
   assert.equal(body.status, "completed");
   assert.equal(body.creditsCharged, 1);
 });
+
+test("emits persistence snapshots on mutating actions", () => {
+  const snapshots = [];
+  const app = createApp({
+    onMutation(state) {
+      snapshots.push(state);
+    },
+  });
+
+  call(app, {
+    method: "POST",
+    path: "/app/actions/topup",
+    headers: { cookie: "xartaudio_user=alice" },
+    body: "amount=5",
+  });
+
+  call(app, {
+    method: "POST",
+    path: "/app/actions/simulate-mention",
+    headers: { cookie: "xartaudio_user=alice" },
+    body: "title=Persisted&body=hello",
+  });
+
+  assert.equal(snapshots.length >= 2, true);
+  const latest = snapshots[snapshots.length - 1];
+  assert.equal(latest.version, 1);
+  assert.equal(typeof latest.updatedAt, "string");
+  assert.equal(typeof latest.engine, "object");
+});