solana-orderbook: serve the persisted solver competition

[anxolin]

Description

Solvers, accounting and the explorer can't see who bid what on Solana.

The autopilot persists every competition the db. This PR is about exposing it.

Linear: BE-315

Changes

Exposes the endpoints and swagger docs for:

• GET /api/v2/solver_competition/{auction_id}
• GET /api/v2/solver_competition/by_tx_hash/{tx_signature}.

The response has the same shape as the EVM except:

• Solana-specific differences: auctionStartSlot/auctionDeadlineSlot instead of blocks
• transactionSignatures/txSignature (base58) instead of hashes
• noclearingPrices or fastPath, because the Solana tables have neither. (for now)

Visibility:

• A competition stays hidden (404) until the current auction's tip_slot in solana.auctions passes its deadline_slot, so solutions are never shown while they can still be submitted. EVM does the same with hide_competition_before_block.

Out of scope

• The per-solution txSignature stays null until the outcome verifier (BE-197) fills settlements.solution_uid.

Open questions for review:

• The path keeps the EVM name by_tx_hash for client parity, even though the parameter is a signature. Happy to rename it to by_tx_signature.
• latest and the unfiltered /restricted variant are not included, because BE-315 doesn't ask for them.

How to test

cargo test -p solana-orderbook --lib solver_competition
# needs a local Postgres with the solana.* schema applied
cargo test -p solana-orderbook --lib solana_db_reads_a_competition_after_its_deadline -- --ignored

Against staging once deployed:

curl -s https://barn.api.cow.fi/solana/api/v2/solver_competition/<auction_id> | jq
curl -s https://barn.api.cow.fi/solana/api/v2/solver_competition/by_tx_hash/<signature> | jq

[linear-code]

BE-315

[github-actions]

Reminder: Please consider backward compatibility when modifying the API specification.
If breaking changes are unavoidable, ensure:

• You explicitly pointed out breaking changes.
• You communicate the changes to affected teams (at least Frontend team and SAFE team).
• You provide proper versioning and migration mechanisms.

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Caused by:

• crates/solana-orderbook/openapi.yml

[anxolin]

I just wanted to check the changes needed to expose it