Bind each customer to a Verae userId for hop tracing

Signup registers/binds a Verae central user and stores veraeUserId. Public access stays the zappier API key. Chain JWTs stay server-side behind tokenRef. Authz, billing, and jobs.watch carry veraeUserId.

packages/verae-zapier-middleware/src/lib/identity.js

@@ -0,0 +1,16 @@
+/**
+ * Stable Verae user id derived from username/email.
+ * Live /auth/login.user.id wins when present; this is the mock/offline id.
+ */
+import { createHash } from 'node:crypto';
+
+export function normalizeVeraeUsername(username) {
+  return String(username || '')
+    .trim()
+    .toLowerCase();
+}
+
+export function stableVeraeUserId(username) {
+  const n = normalizeVeraeUsername(username);
+  return `vu_${createHash('sha256').update(n).digest('hex').slice(0, 16)}`;
+}