[codex] add evm-only giga executor path

[codchen]

Summary

• add giga/evmonly as the final-form EVM-only giga execution path boundary
• define raw Ethereum RLP block input and commit-neutral outputs as an EVM-native state changeset plus receipts
• port the core sei-v3-style execution shape directly into giga/evmonly:
  • raw RLP tx parsing and sender recovery
  • go-ethereum execution against an SDK-free native vm.StateDB
  • key-addressable EVM-native balance, nonce, code, and storage state reads
  • deterministic post-block StateChangeSet output
  • Ethereum receipt and per-tx metadata construction
• add a map-backed MemoryState backend for tests and early integration
• leave custom precompiles as fail-closed placeholders behind an SDK-free registry/context
• refresh the README to describe the current implementation, input/output contract, and known limitations

Notes

Custom precompile behavior is intentionally still open. Registered custom precompile addresses return ErrCustomPrecompilesOpen, including through geth's precompile map, so calls fail closed instead of silently executing as empty accounts.

The current port is sequential. The state boundary and changeset shape are intended to be replaceable with the sei-v3 OCC scheduler/store once that layer is brought over.

Historical BLOCKHASH lookups beyond the parent block are not wired yet; BlockHash is currently used for receipt/log metadata.

Validation

go test ./giga/evmonly/...
go test ./giga/...

[codecov]

Codecov Report

❌ Patch coverage is 62.25266% with 248 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.09%. Comparing base (f79b5fd) to head (966d056).

Files with missing lines	Patch %	Lines
giga/evmonly/state_db.go	54.08%	161 Missing and 19 partials ⚠️
giga/evmonly/executor.go	73.82%	26 Missing and 13 partials ⚠️
giga/evmonly/state.go	76.13%	17 Missing and 4 partials ⚠️
giga/evmonly/parser.go	60.00%	5 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3583      +/-   ##
==========================================
- Coverage   58.95%   58.09%   -0.86%     
==========================================
  Files        2211     2142      -69     
  Lines      182172   174282    -7890     
==========================================
- Hits       107397   101247    -6150     
+ Misses      65148    64070    -1078     
+ Partials     9627     8965     -662     

Flag	Coverage Δ
sei-chain-pr	62.25% <62.25%> (?)
sei-db	70.41% <ø> (ø)
sei-db-state-db	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
giga/evmonly/config.go	100.00% <100.00%> (ø)
giga/evmonly/parser.go	60.00% <60.00%> (ø)
giga/evmonly/state.go	76.13% <76.13%> (ø)
giga/evmonly/executor.go	73.82% <73.82%> (ø)
giga/evmonly/state_db.go	54.08% <54.08%> (ø)

... and 74 files with indirect coverage changes

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[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Jun 17, 2026, 2:39 AM

[cursor]

PR Summary

Medium Risk
New core execution and state-transition code affects balances, nonces, and gas policy, but it is isolated in a new package with tests and no app integration yet.

Overview
Introduces giga/evmonly, a Cosmos-free execution boundary for the final-form giga path: ordered blocks of raw Ethereum RLP txs in, commit-neutral StateChangeSet plus Ethereum receipts and per-tx metadata out.

The Executor runs go-ethereum sequentially via core.ApplyMessage on an SDK-free nativeStateDB backed by a pluggable StateReader (default MemoryState for tests). It builds deterministic post-block balance/nonce/code/storage writes, enforces optional min gas price and nonce policy, and documents input/output contracts in the new README.

Custom precompiles get an SDK-free registry/context shape, but registered addresses are wired to fail-closed stubs returning ErrCustomPrecompilesOpen. Known gaps called out: sequential-only execution, parent-only BLOCKHASH, and no real precompile port yet.

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