Implement Light Client Header Chain Synchronization Service

[kingofthebongo2008]

Description

Per Architecture.md's Light Sync section, the system needs a LightClient class that syncs block headers from a trusted checkpoint to track the chain tip. This is essential for consensus verification without downloading full blocks.

Features described in Architecture:

• Request headers from trusted checkpoint
• Verify chain-specific consensus
• Track chain tip for monitoring

Acceptance Criteria

• Create include/rlpx/sync/light_client.hpp
• Implement LightClient class with checkpoint-based sync
• Add syncHeaders(startHash, count) coroutine method
• Implement header chain validation (parent hash linkage)
• Maintain local header cache with configurable depth
• Provide getLatestHeader() for current chain tip
• Add callback for new headers received
• Add integration tests with testnet
• Use coroutines for async operations

Priority

Medium

Related Requirements

• CLAUDE.md: Prefer to use coroutines for high latency operations like network io
• Architecture.md: Light Client - Connect to each chain's P2P network, sync block headers
• Issue EVM Bridging Messaging System #2: Maintains synchronization between source and destination chains