Returns project-wide attributed conversions for ingestion pipelines. Each result is one attribution row
(attributed conversion event) that has at least one payout. Payout amounts per referral level (L1–L4) are
nested under payouts.

Authentication:

• Requires API key with service_role scope in the Authorization header: Authorization: Bearer <api_key>
• The project is automatically derived from the API key's associated project

Pagination:

• limit controls how many attribution rows are returned per request (default 500, max 1000)
• after_id is a cursor on attribution_id
• count equals the number of attribution rows in results

Incremental loads:

• created_since filters attributions with created_at > value
• updated_since filters attributions with updated_at > value, or any child payout with updated_at > value
• Periodic full backfills are recommended for long-running pipelines