Hybrid Hyperliquid adapter (bridge + API + attestation), not contract-to-contract

Context

HIP-3 perps run on the Hyperliquid L1 Rust binary, not as on-chain EVM contracts. The Hyperliquid contracts repo contains only Bridge2.sol.

Decision

Portico to Hyperliquid uses the bridge for collateral, an off-chain API for order placement, and an on-chain attestation of position state.

Alternatives

Skip Hyperliquid (rejected: it is the wedge, the biggest cross-margin demand source). Wait for an HL EVM (rejected: not on the roadmap).

Consequences

Adapter complexity is higher than pure contract-to-contract. An attest_off_chain_state(...) method was added to the IPorticoAdapter v1.0 interface for hybrid adapters.