refactor(blockchain): remove log_tree param from accept_new_attestations

[Aliemeka]

🗒️ Description / Motivation

• Removes the log_tree boolean parameter from accept_new_attestations (and update_head), which threaded a UI concern through the fork-choice code path.
• crates/blockchain/src/store.rs is meant to mirror the spec's architecture, and the log_tree flag was inconsistent with that goal — logging is a caller-side concern, not part of the fork-choice update.
• Moves the fork choice tree logging to the call site (on_tick, end-of-slot) so the update functions stay purely about fork-choice computation.

What Changed

• crates/blockchain/src/store.rs
  • Dropped the log_tree: bool parameter from accept_new_attestations and update_head.
  • Added a standalone log_fork_choice_tree(store, &HeadUpdate) helper that renders the ASCII tree; called from on_tick at SlotInterval::EndOfSlot.
  • update_head now returns a HeadUpdate { blocks, weights, head } so the tree renders from already-computed data instead of recomputing LMD GHOST.
  • Updated the (previously stale) update_head doc comment.
• crates/blockchain/src/spec_test_runner.rs
  • Updated the update_head call to the new no-bool signature.

Correctness / Behavior Guarantees

• No behavior change. The tree is still logged only at end-of-slot, and log_fork_choice_tree still reads latest_justified/latest_finalized after the checkpoint update — so the rendered tree is byte-for-byte equivalent to before.
• Efficiency improvement: end-of-slot previously computed LMD GHOST twice (once in update_head, once for the tree). It now computes once and reuses the result via HeadUpdate, eliminating a redundant get_live_chain() + compute_lmd_ghost_head() per slot.
• All other call sites (BlockPublication, on_block_core, get_proposal_head) simply drop the false argument — no functional difference.

Tests Added / Run

• No new tests — this is a behavior-preserving refactor covered by existing fork-choice spec tests.
• Ran:
  • cargo clippy -p ethlambda-blockchain --all-targets -- -D warnings — clean
  • cargo fmt --all --check — clean
  • cargo test -p ethlambda-blockchain --test forkchoice_spectests — compiled and ran; requires make leanSpec/fixtures locally to execute assertions.

Related Issues / PRs

• Closes Remove the log_tree parameter on accept_new_attestations #520

✅ Verification Checklist

• Ran make fmt — clean
• Ran make lint (clippy with -D warnings) — clean
• Ran cargo test --workspace --release

[greptile-apps]

Greptile Summary

This PR moves fork-choice tree logging out of the head update functions. The main changes are:

• Returns computed blocks, weights, and head in a new HeadUpdate value.
• Logs the tree from the end-of-slot caller without recomputing LMD GHOST.
• Updates callers to use the simplified function signatures.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• The head is still committed before HeadUpdate is returned.
• End-of-slot logging uses the same computed data and checkpoint ordering as before.

Important Files Changed

Filename	Overview
crates/blockchain/src/store.rs	Moves tree logging to end-of-slot processing and returns the existing fork-choice computation through HeadUpdate.
crates/blockchain/src/spec_test_runner.rs	Updates the test runner for the simplified update_head signature.

_{Reviews (1): Last reviewed commit: "refactor(blockchain): remove log_tree pa..." | Re-trigger Greptile}

[MegaRedHand]

Great work