Implement Merkle Proof Verification for Cross-Chain State Proofs

[kingofthebongo2008]

Description

Issue #2 specifies that the bridge must 'Validates cross-chain messages using RLP-encoded state proofs' and 'Verify Merkle proofs and state data integrity.' Currently, there is no Merkle proof verification implementation in the repository.

This is critical for:

• Verifying inclusion of transactions in blocks
• Validating state proofs for bridge operations
• Cross-chain message verification

Acceptance Criteria

• Create include/rlp/rlp_merkle.hpp for Merkle proof types
• Implement MerkleProof struct (list of sibling hashes, path)
• Implement verifyMerkleProof(root, leaf, proof) -> bool function
• Implement Patricia Merkle Trie proof verification for Ethereum state proofs
• Support both transaction trie and receipt trie proofs
• Add Keccak-256 hash utility (or integrate with existing crypto)
• Add unit tests with real Ethereum mainnet proofs
• All functions noexcept with Result return types

Priority

High

Related Requirements

• CLAUDE.md: Exception Handling - generate code without exception handling by default
• CLAUDE.md: Outcome-based errors - No exceptions in hot paths
• Issue EVM Bridging Messaging System #2: Processes Merkle proof data for cross-chain verification