Journal response schemas corrected for JNLC and JNLS

Broker API

Corrects how journal responses are described so they match the wire response.

• Journal is now a union of the complete JNLC and JNLS schemas, both composed from a shared JournalBase and selected by entry_type.
• Batch journal responses are modeled as BatchJournalResponseJNLC and BatchJournalResponseJNLS, also selected by entry_type, with an optional error_message on a failed item.
• The reverse batch endpoint now documents an array of JNLC objects. If any account or entry is invalid the whole batch is canceled, and no per-item error result is returned.
• Required and nullable journal fields (symbol, qty, price, settle_date, system_date, net_amount) and the response examples have been corrected.
• legs on the OrderLeg schema is documented as always null, and an empty array is accepted for generated-client compatibility. Legs are still never nested beyond one level.

Affected Endpoints

• POST /v1/journals
• GET /v1/journals
• GET /v1/journals/{journal_id}
• POST /v1/journals/batch
• POST /v1/journals/reverse_batch
• POST /v1/trading/accounts/{account_id}/orders
• GET /v1/trading/accounts/{account_id}/orders
• GET /v1/trading/accounts/{account_id}/orders/{order_id}
• GET /v1/trading/accounts/{account_id}/orders:by_client_order_id
• PATCH /v1/trading/accounts/{account_id}/orders/{order_id}
• DELETE /v1/trading/accounts/{account_id}/orders
• POST /v1/trading/accounts/{account_id}/orders/estimation
• DELETE /v1/trading/accounts/{account_id}/positions
• DELETE /v1/trading/accounts/{account_id}/positions/{symbol_or_asset_id}
• GET /v1/rebalancing/runs
• GET /v1/rebalancing/runs/{run_id}
• GET /v2/events/trades