STR-1684: EE P2P broadcast/gossip of head block hash

[storopoli]

Description

Custom RLPx subprotocol to gossip the head block hash in alpen-reth and reth-node.

Blocked 🪨 by #1035 which has the PreConsensusTracker trait that this PR should use.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature/Enhancement (non-breaking change which adds functionality or enhances an existing one)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactor
• New or updated tests
• Dependency Update

Notes to Reviewers

Checklist

• I have performed a self-review of my code.
• I have commented my code where necessary.
• I have updated the documentation if needed.
• My changes do not introduce new warnings.
• I have added (where necessary) tests that prove my changes are effective or that my feature works.
• New and existing tests pass with my changes.
• I have disclosed my use of AI
  in the body of this PR.

Related Issues

STR-1684

[github-actions]

Commit: cbf9df3

SP1 Execution Results

program	cycles	success
Bitcoin Blockspace	70,870	✅
EVM EE STF	1,172,673	✅
CL STF	377,821	✅
Checkpoint	4,229	✅

[storopoli]

@sapinb please take a look at this.
See if this the approach that you were thinking with implementing a custom RLPx subprotocol to gossip the head block hash.

Maybe we should just gossip the FixedBytes<32> for the actual block hash instead of the very complex Header?