Milestone 0: import zappier billing, Verae middleware, and Zapier research

Compose-ready workspace: packages/zappier (rate card, portal, Stripe),
packages/verae-zapier-middleware (timestamp + NATS), packages/verae-zapier
(CLI app), vendor/zapier-platform, and research/zapier vendor corpus.

Gate 0 structure checks pass. Product code and research are not yet wired.

vendor/zapier-platform/example-apps/openai/constants.js

@@ -0,0 +1,10 @@
+const BASE_URL = 'https://api.openai.com';
+const VERSION = 'v1';
+const API_URL = `${BASE_URL}/${VERSION}`;
+
+const DEFAULT_MODEL = 'gpt-4o-mini';
+
+module.exports = {
+  API_URL,
+  DEFAULT_MODEL,
+};