chore: improve API latency of v1/get_trades

[m-sz]

Background

During high user activity, the latency of v1/get_trades deteriorates. The API call does not support pagination, so it can cause slowdowns if a lot of trades are happening for a particular user.

Details

The OpenAPI spec for GET on v1/trades allows one to specify either an order uid or owner address. The returned results are not paginated and can potentially query a lot of data.

Implement pagination for the v1/get_trades in orderbook.

Acceptance criteria

• Pagination feature implemented and merged
• Tested on production traffic that the API latency spike no longer occurs.

[squadgazzz]

It was already discussed with the FE team that they would need to implement an adoption in advance, and only then we can proceed with implementation from our end.

[Grinsven]

I noticed this is blocked waiting for frontend pagination support. I checked the cowswap repository and don't see any active work on this yet.

I'd like to tackle both the frontend and backend implementation if no one else has started. The approach would be:

1. Frontend first: Add pagination parameters (limit/offset or cursor-based) to the trades API calls
2. Backend second: Implement pagination in the orderbook's GET /api/v1/trades endpoint

Is this still needed and available to work on?