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.

docs/developer/modules/workers.md

@@ -0,0 +1,35 @@
+# Module: `workers`
+
+**Path:** `verae-zapier-middleware/src/workers/`  
+**Phases:** 6 (in-process), 8–9 (NATS)
+
+## Files
+
+| File | Phase | Purpose |
+|------|-------|---------|
+| `inProcessJobPoller.js` | 6 | Fallback poller when `NATS_ENABLED=false` |
+| `jobPollerWorker.js` | 8 | JetStream job watch consumer |
+| `webhookWorker.js` | 8 | JetStream webhook deliver consumer |
+
+## `startJobPollerWorker()`
+
+| | |
+|--|--|
+| **For** | Poll Verae until job terminal; publish events |
+| **Input** | none (uses NATS + config) |
+| **Output** | `Promise<{ stop: () => Promise<void> }>` |
+| **Debug** | `jobs`, `http`, `nats` |
+
+## `startWebhookWorker()`
+
+| | |
+|--|--|
+| **For** | POST completion payloads to Zapier hook URLs |
+| **Output** | `Promise<{ stop: () => Promise<void> }>` |
+| **Debug** | `webhooks`, `nats` |
+
+## Rules
+
+- Only one of in-process poller **or** NATS job worker should run.
+- Never log raw JWTs or full webhook secrets.
+- Queue groups allow horizontal scale without double delivery.