Adding rpc package with ethereum json rpc compatible methods + tests

[otherview]

Description

Ethereum Compatibility: EIP-1559 Transactions & JSON-RPC Server

This PR adds first-class support for Ethereum EIP-1559 transactions to VeChain Thor and exposes an Ethereum-compatible JSON-RPC endpoint, enabling standard Ethereum tooling
(MetaMask, ethers.js, viem, Hardhat, Foundry) to interact with VeChain nodes without modification.

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What's new

New transaction type: TypeEthTyped1559 (0x02)

A new native transaction type that conforms to the Ethereum EIP-1559 wire format (0x02 || RLP(body)), gated behind the new INTERSTELLAR fork:

• Wire format: standard EIP-1559 (chainId, nonce, maxPriorityFeePerGas, maxFeePerGas, gasLimit, to, value, data, accessList, yParity, r, s)
• Chain ID: derived deterministically from the genesis block ID via thor.GetEthChainID() — no config needed
• Replay protection: chain ID replaces VeChain's chain tag for these transactions
• Signature validation: low-S enforcement, ECDSA recovery, zero-sender rejection
• Sender nonce: state.GetNonce / state.SetNonce tracks per-account ETH nonces in the state trie, matching Ethereum semantics
• Fee model: EIP-1559 effective gas price (min(maxFeePerGas, baseFee + maxPriorityFeePerGas)) integrated into the existing GALACTICA fee deduction path
• Block accounting: txFitsBlockSize enforced post-INTERSTELLAR; block GasUsed includes ETH tx gas
• Consensus: validateBlockBody rejects malformed ETH txs, enforces field ranges and signature bounds
• EthBuilder: tx.NewEthBuilder(TypeEthTyped1559) builder API for constructing and signing ETH transactions in Go

Ethereum JSON-RPC server (rpc/)

A new root-level rpc/ package (mirroring the structure of api/) implements a JSON-RPC 2.0 server exposing standard Ethereum methods. Launched separately from the REST API on its own
port.

Key projection semantics: VeChain blocks can contain a mix of native and ETH transactions. The JSON-RPC server projects only TypeEthTyped1559 transactions into the Ethereum-visible view — native transactions are invisible to ETH tooling.

Node wiring

• New --eth-rpc-addr flag (default localhost:8646) starts the Ethereum JSON-RPC server alongside the existing REST API
• cmd/thor/httpserver/eth_rpc_server.go assembles all sub-packages onto a dispatcher and applies CORS

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Out of scope (tracked as TODOs)

• Access lists (EIP-2930): rejected at the engine level until EIP-2929 warm/cold gas accounting is implemented in the VM
• Mempool nonce validation: sequential nonce enforcement deferred to dedicated mempool work
• Log bloom filters: logsBloom in blocks and receipts returns a zero placeholder
• Merkle roots: transactionsRoot and receiptsRoot return zero hashes
• OR-within-position topic filters in eth_getLogs: only the first alternative per position is used

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Tests

• Each rpc/ sub-package has a focused handler_test.go testing only its own methods in isolation
• rpc/integration_test.go covers server- and dispatcher-level behaviour (batch processing, batch size limit, method-not-found, invalid JSON, wrong HTTP method)
• rpc/testutil provides a shared ChainFixture (genesis + 1 block with both a native and an ETH tx) and helpers used across all sub-package tests
• thorclient/rpc_test.go provides end-to-end integration tests across the full two-block chain: block retrieval, transaction visibility (ETH visible / VeChain invisible), receipt
  transactionIndex and cumulativeGasUsed assertions, fee history, simulation, and a full send → mine → read cycle via eth_sendRawTransaction

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• New and existing E2E tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have not added any vulnerable dependencies to my code

[codecov-commenter]

Codecov Report

❌ Patch coverage is 50.90703% with 866 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
rpc/ethconvert/utils.go	13.54%	132 Missing and 2 partials ⚠️
rpc/testutil/testutil.go	0.00%	97 Missing ⚠️
rpc/ethconvert/eth_types.go	17.30%	86 Missing ⚠️
rpc/ethconvert/log_criteria.go	0.00%	77 Missing ⚠️
rpc/jsonrpc/server.go	0.00%	63 Missing ⚠️
rpc/filters/handler.go	79.56%	25 Missing and 22 partials ⚠️
rpc/ws/conn.go	73.65%	28 Missing and 16 partials ⚠️
rpc/accounts_types.go	0.00%	39 Missing ⚠️
rpc/transactions_types.go	0.00%	38 Missing ⚠️
rpc/transactions/handler.go	70.21%	14 Missing and 14 partials ⚠️
... and 16 more

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