feat(solana-solvers): PR 2.2 buy orders via Jupiter v1 API

[squadgazzz]

Description

Buy-order support for the Jupiter solver, split out from PR2 and gated off by default. Both sides share the v1 path: PR2 quotes sells with ExactIn, this adds ExactOut for buys. Stacked on PR2.

Changes

• enable_buy_orders config flag, off by default. While off, buy orders return OrderNotSupported.
• swap() picks swapMode per side: ExactIn for sells, ExactOut for buys. Same /swap/v1/quote + /swap-instructions path and DTO as sells, no new response type.

How to test

New unit test (buy gated off). Live #[ignore] buy test (ExactOut): cargo test -p solana-solvers -- --ignored jupiter_live (keyless works, JUPITER_API_KEY optional).

[claude]

Claude finished @squadgazzz's task in 1m 42s —— View job

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PR Review: buy orders via v1 ExactOut

• Read diff against origin/solana-solvers/PR2-jupiter-adapter
• Review config.rs, mod.rs, dto.rs, and call sites
• Post findings

Verdict: LGTM. The change is small, focused, and correctly gated. The SwapMode enum reads better than the previous stringly-typed &str, buy orders remain rejected with OrderNotSupported while the flag is off, and both sides share the same /quote + /swap-instructions path and DTO as advertised. Config default (#[serde(default)], off) and the renamed tests are all consistent.

No change-worthy issues to flag inline.

One non-blocking observation for a later PR (not this one — /solve is still a scaffold so swap() isn't wired into solving yet): for ExactOut, slippageBps bounds the input, so the actual sell amount can exceed the quoted inAmount by up to the slippage. Swap.in_amount here is the quoted mid input, not the worst case. When solution accounting is wired up, whoever reserves sell tokens will need the slippage-adjusted max rather than the quoted in_amount (the mirror concern exists for sells' out_amount). Worth keeping in mind, nothing to do here.

Note: I couldn't run cargo check/tests in this environment (command approval denied), but the change is mechanical (enum + config field + test rename) and reads as compiling correctly.
· solana-solvers/PR2.2-buy-orders