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.

packages/zappier/src/paths.ts

@@ -0,0 +1,9 @@
+import path from 'path';
+
+/**
+ * Absolute path of the project root, resolved from this module's location so
+ * the app works from any working directory (systemd, Docker, cron, `node
+ * dist/index.js` from elsewhere). Holds for both layouts: ts-node running
+ * src/ (root is one level up) and compiled dist/ (same one level up).
+ */
+export const PROJECT_ROOT = path.join(__dirname, '..');