Create ledger.js

ledger.js

@@ -0,0 +1,37 @@
+// ledger.js
+
+const fs = require('fs');
+const path = require('path');
+
+const LEDGER_DIR = path.join(__dirname, 'ledger');
+
+function ensureLedgerDir() {
+  if (!fs.existsSync(LEDGER_DIR)) {
+    fs.mkdirSync(LEDGER_DIR);
+  }
+}
+
+function timestampForFilename() {
+  const now = new Date();
+  const iso = now.toISOString(); // e.g. 2026-06-28T16:12:34.567Z
+  return iso.replace(/[:.]/g, '-');
+}
+
+function writeLedgerEntry(entry) {
+  ensureLedgerDir();
+
+  const filename = `${timestampForFilename()}.json`;
+  const filepath = path.join(LEDGER_DIR, filename);
+
+  const payload = {
+    engineVersion: 'v0.2-ledger',
+    createdAt: new Date().toISOString(),
+    entry,
+  };
+
+  fs.writeFileSync(filepath, JSON.stringify(payload, null, 2), 'utf8');
+
+  return filepath;
+}
+
+module.exports = { writeLedgerEntry };