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/nats.md

@@ -0,0 +1,28 @@
+# Module: `nats`
+
+**Path:** `verae-zapier-middleware/src/nats/`  
+**Phase:** 7  
+**Debug namespace:** `nats`
+
+## Files
+
+| File | Purpose |
+|------|---------|
+| `subjects.js` | Subject, stream, consumer name constants |
+| `connection.js` | Connect, ensure streams, close |
+| `publishers.js` | enqueueWatch, publishJobEvent, enqueueWebhook |
+
+## Function contracts
+
+Full I/O tables: [function-reference.md](function-reference.md#natssubjectsjs)  
+Payload schemas: [../../architecture/nats-subjects.md](../../architecture/nats-subjects.md)
+
+## Implementation status
+
+Stubs throw until **GATE 7**. Call sites must check `config.natsEnabled` and fall back to in-process poller (Phase 6).
+
+## Security
+
+- Prefer `tokenRef` over raw Verae JWT in messages.
+- All publish paths log via `createDebugger('nats')` with redaction.
+- NATS must remain private (not exposed to Zapier).