feat(sdk): support hyper_evm and polygon

[DSharifi]

closes #2815
closes #2816

[claude]

Pull request overview

Adds SDK builders for two new EVM-compatible foreign chains, HyperEvm and Polygon, mirroring the existing pattern used for Arbitrum/Base/Bnb. New variants are appended to ForeignChainRpcRequest and ForeignChain in the contract-interface crate, and exhaustiveness is preserved (matches were updated; downstream callers either use the _ => bail!(…) arm or are wildcard-aware via #[non_exhaustive]).

Changes:

• New ForeignChainRpcRequest::HyperEvm / Polygon variants and corresponding ForeignChain enum entries, with the chain() mapping updated and rstest cases added.
• New near_mpc_sdk::foreign_chain::hyper_evm and polygon modules implementing EvmChainVariant plus new_hyper_evm() / new_polygon() builders.
• Integration tests tests/hyper_evm.rs and tests/polygon.rs mirroring the Bnb/Base/Arbitrum tests.

Reviewed changes

Per-file summary

File	Description
crates/near-mpc-contract-interface/src/types/foreign_chain.rs	Adds HyperEvm/Polygon variants to ForeignChainRpcRequest and ForeignChain, updates chain() match, and extends rstest cases.
crates/near-mpc-sdk/src/foreign_chain.rs	Registers new hyper_evm and polygon submodules.
crates/near-mpc-sdk/src/foreign_chain/hyper_evm.rs	New chain variant marker, EvmChainVariant impl, builder constructor, and unit test.
crates/near-mpc-sdk/src/foreign_chain/polygon.rs	Same as above for Polygon.
crates/near-mpc-sdk/tests/hyper_evm.rs	Integration test asserting the request wraps to the HyperEvm variant with no extractors.
crates/near-mpc-sdk/tests/polygon.rs	Same as above for Polygon.

Findings

Non-blocking (nits, follow-ups, suggestions):

• crates/node/src/providers/verify_foreign_tx/sign.rs:274 — heads-up that signing requests for HyperEvm/Polygon will hit the _ => bail!(\"unsupported foreign chain request\") arm at runtime, since the node binary has no inspector/config wiring for these chains. This is consistent with the PR title (feat(sdk): …), but it means a client built with this SDK can produce requests the node will reject — worth a follow-up issue (or noting in the PR description) to track the node-side support and config fields in crates/node-config/src/foreign_chains.rs.
• crates/near-mpc-sdk/tests/hyper_evm.rs:8 and crates/near-mpc-sdk/tests/polygon.rs:8 — fn no_extractor_added() doesn't follow the <system_under_test>__should_<assertion> convention from docs/engineering-standards.md. Mirrors the existing bnb.rs/arbitrum.rs tests, so not introduced by this PR, but a good opportunity to convert if you're touching them.

✅ Approved

[DSharifi]

@claude review

[claude]

Pull request overview

Adds near_mpc_sdk builder modules and integration tests for two additional EVM-compatible foreign chains (HyperEvm and Polygon), mirroring the existing Bnb/Base/Arbitrum pattern. The corresponding ForeignChainRpcRequest::{HyperEvm,Polygon} variants already landed on main via #3149 (the inspector PR), so this is a pure SDK ergonomics addition — no contract or wire-format changes.

Changes:

• New near_mpc_sdk::foreign_chain::hyper_evm and polygon modules: marker structs, EvmChainVariant impls, new_hyper_evm() / new_polygon() builder constructors, and one builder unit test each.
• New tests/hyper_evm.rs and tests/polygon.rs integration tests asserting the built request wraps into the correct variant with no extractors.

Reviewed changes

Per-file summary

File	Description
crates/near-mpc-sdk/src/foreign_chain.rs	Registers the two new chain submodules.
crates/near-mpc-sdk/src/foreign_chain/hyper_evm.rs	New HyperEvm variant marker, EvmChainVariant::wrap impl, new_hyper_evm() builder, and unit test asserting the variant wrap.
crates/near-mpc-sdk/src/foreign_chain/polygon.rs	Same as above for Polygon.
crates/near-mpc-sdk/tests/hyper_evm.rs	Integration test verifying the HyperEvm variant has empty extractors when none are configured.
crates/near-mpc-sdk/tests/polygon.rs	Same as above for Polygon.

Findings

No blocking issues. The two heads-ups raised in the prior @claude review (node-side _ => bail!("unsupported foreign chain request") at crates/node/src/providers/verify_foreign_tx/sign.rs:274 for these new variants, and the no_extractor_added test naming not matching the <sut>__should_<assertion> convention) still stand but are non-blocking and consistent with the existing chain modules.

✅ Approved