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/samples/chat.json

@@ -0,0 +1,29 @@
+{
+  "id": "chatcmpl-123",
+  "object": "chat.completion",
+  "created": 1677652288,
+  "model": "gpt-4o-mini",
+  "system_fingerprint": "fp_44709d6fcb",
+  "choices": [
+    {
+      "index": 0,
+      "message": {
+        "role": "assistant",
+        "content": "\n\nHello there, how may I assist you today?"
+      },
+      "logprobs": null,
+      "finish_reason": "stop"
+    }
+  ],
+  "service_tier": "default",
+  "usage": {
+    "prompt_tokens": 9,
+    "completion_tokens": 12,
+    "total_tokens": 21,
+    "completion_tokens_details": {
+      "reasoning_tokens": 0,
+      "accepted_prediction_tokens": 0,
+      "rejected_prediction_tokens": 0
+    }
+  }
+}