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/test/integration/tenants.test.js

@@ -44,6 +44,8 @@ describe('tenancy', () => {
     const body = await res.json();
     assert.equal(body.tenant.plan, 'free');
     assert.ok(body.apiKey.startsWith('zmw_'));
+    assert.match(body.tenant.veraeUserId, /^vu_[0-9a-f]{16}$/);
+    assert.doesNotMatch(JSON.stringify(body), /mock-jwt|eyJhbGci/);
   });
 
   it('enterprise without contract rejected', async () => {