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/dynamic_dropdowns/index.js

@@ -0,0 +1,7 @@
+/* eslint-disable camelcase */
+const list_models = require('./list_models.js');
+
+// If you add a new Dynamic Dropdown, make sure it is exported here to display in the Zapier Editor
+module.exports = {
+  [list_models.key]: list_models,
+};