Fork choice on_execution_payload skeleton

[StefanBratanov]

PR Description

Simple implementation (more of a skeleton) for fork_choice#on_execution_payload. Also created a new ForkChoicePayloadExecutorGloas which is catered for Gloas.

Fixed Issue(s)

related to #9878

Documentation

• I thought about documentation and added the doc-change-required label to this PR if updates are required.

Changelog

• I thought about adding a changelog entry, and added one if I deemed necessary.

---

Note

Adds fork choice handling for Gloas execution payload envelopes, updates executor API to use Optional header, and introduces debug/P2P logging plus related helpers and tests.

• Fork Choice:
  • Implement onExecutionPayload for Gloas: retrieves state via SlotAndBlockRoot, validates/processes envelope, runs EL via ForkChoicePayloadExecutorGloas, (NOOP) DA check, applies to store via ForkChoiceUtil.applyExecutionPayloadToStore, and returns detailed ExecutionPayloadImportResult.
  • Add result mapping and invalid payload reporting (reportInvalidExecutionPayload).
• Executor:
  • New ForkChoicePayloadExecutorGloas to execute engine_newPayload for envelopes; tests added.
  • Change OptimisticExecutionPayloadExecutor#optimisticallyExecute to accept Optional<ExecutionPayloadHeader>; update Bellatrix processor and ForkChoicePayloadExecutor + tests.
• Results/Types:
  • Expand ExecutionPayloadImportResult with new failure reasons and factory methods.
  • SignedExecutionPayloadEnvelope adds getSlot() and getSlotAndBlockRoot().
• Fork Choice Utils (Gloas):
  • Introduce applyExecutionPayloadToStore hook (no-op for now) and Gloas-specific util wiring.
• Debug/Logging:
  • DebugDataDumper and DebugDataFileDumper support saving invalid execution payloads (new invalid_execution_payloads dir) and refine data column sidecar saving.
  • P2PLogger adds onInvalidExecutionPayload.
• Docs/Javadoc:
  • Update references to new Optional executor API in AvailabilityChecker.

^{Written by Cursor Bugbot for commit 1b06696. This will update automatically on new commits. Configure here.}