P7 C Zonos Sandbox Validation Template

# P7-C Zonos Sandbox Validation Template
 
Use this after PR #199 is merged and Zonos sandbox credentials are configured on the API.
 
## 1) Run Matrix
 
Optional preflight (no credentials/network calls):
 
```bash
npx tsx scripts/run-zonos-sandbox-matrix.ts --dry-run
```
 
```bash
API_KEY="<integration-key>" \
ORG_ID="<tenant-uuid>" \
BASE_URL="http://localhost:3001" \
npx tsx scripts/run-zonos-sandbox-matrix.ts
```
 
Optional knobs:
 
```bash
OUTPUT_DIR="tmp/zonos-matrix" REQUEST_DELAY_MS=100 npx tsx scripts/run-zonos-sandbox-matrix.ts
```
 
The runner writes:
- JSON payload: `tmp/zonos-matrix/zonos-matrix-<timestamp>.json`
- Markdown snapshot: `tmp/zonos-matrix/zonos-matrix-<timestamp>.md`
 
## 2) Paste Results
 
### Run Metadata
 
| Field | Value |
|---|---|
| Base URL | |
| Run timestamp (UTC) | |
| Cases | 30 |
| Success / Fail | |
| Error Rate | |
| Max Consecutive Success | |
| P95 Request Latency (ms) | |
| P95 Provider Latency (ms) | |
 
### Go/No-Go Criteria (fill from run output)
 
| Criterion | GO | CONDITIONAL | NO-GO | Observed | Status |
|---|---|---|---|---|---|
| Duty rate accuracy | Delta <= 2% absolute for 80%+ of cases | Delta <= 5% for 80%+ | Delta > 5% for majority | | |
| Tax rate accuracy | Delta <= 2% absolute for 80%+ of cases | Delta <= 5% for 80%+ | Delta > 5% for majority | | |
| p95 latency | <= 2s | <= 5s | > 5s | | |
| API stability | 20 consecutive successes | <= 5% error rate | > 10% error rate | | |
 
### Per-Case Results
 
Copy this from the generated markdown file in `tmp/zonos-matrix/`.
 
## 3) Decision
 
- Decision: `GO` / `CONDITIONAL` / `NO-GO`
- Notes:
- Follow-up actions: