Export tenant usage data

Export email usage data for all tenants in CSV or JSON Lines format. Designed for billing system integration, data warehousing, and analytics.

Jobs to be done:

• Import usage data into billing systems (Stripe, Chargebee, etc.)
• Load into data warehouses (Snowflake, BigQuery, etc.)
• Process in spreadsheets (Excel, Google Sheets)
• Feed into BI tools (Looker, Metabase, etc.)

Export formats:

• csv - UTF-8 with BOM for Excel compatibility (default)
• jsonl - JSON Lines (one JSON object per line, streamable)

CSV columns: tenant_id, tenant_name, external_id, status, sent, delivered, soft_failed, hard_failed, bounced, held, delivery_rate, bounce_rate, period_start, period_end

Response headers:

• Content-Disposition - Filename for download
• Content-Type - text/csv or application/x-ndjson

[
  {
    "tenant_id": "cm6abc123def456",
    "tenant_name": "Acme Corp",
    "external_id": "acme_123",
    "status": "active",
    "sent": 10000,
    "delivered": 9700,
    "soft_failed": 100,
    "hard_failed": 50,
    "bounced": 100,
    "held": 50,
    "delivery_rate": 0.97,
    "bounce_rate": 0.015
  }
]