feat(node): Backport Follow Mode For v1.3.2

[refcell]

Summary

Backports the unified binary follow mode from #4994 onto the releases/v1.3.2 release branch. This cherry-picks the three commits that add follow mode to the unified base binary along with the rustfmt and clippy cleanups. The commits applied cleanly with no conflicts. Note that #4994 is still open on main at the time of this backport, so this branch may need to be refreshed if that PR changes before it merges.

[github-actions]

Review Summary

PR: Backport Follow Mode for v1.3.2

This PR adds a base follow subcommand to the unified binary, running an execution node and consensus follow node in a single process. The follow node reads canonical payloads from a source L2 RPC and inserts them via the embedded execution node's IPC engine socket.

Assessment: No blocking findings.

The implementation closely mirrors the existing base rpc command structure, which reduces risk:

• Shutdown coordination (tokio::select! in bin/base/src/commands/follow.rs:112-130) correctly handles both execution-exits-first and follow-exits-first cases, matching the pattern in rpc.rs.
• Engine endpoint override is correctly enforced: FollowNodeOverrides::embedded_execution(l2_engine_rpc) always provides Some(url), so the placeholder from EmbeddedL2ClientArgs → L2ClientArgs conversion is never reached in the embedded path.
• CLI flag namespacing (--follow.proofs, --follow.proofs.max-blocks-ahead, --follow.insert-delay-ms) avoids collisions with execution-layer flags when flattened into the unified command.
• Cancellation propagation via CancellationToken and start_with_cancellation on FollowNode is clean, and the follow node also respects ShutdownSignal internally.
• No .unwrap()/.expect() in non-test code, error handling is consistent with ? and map_err.
• Not block-production-sensitive — follow mode is a follower/validator path, not a builder/sequencer path.

Tests cover CLI argument parsing, proofs flag defaults, and rejection of the --l2-engine-rpc flag (which must come from the embedded execution node).

[github-actions]

Base Std historical fork tests

Fork	Result	Passed	Failed	Skipped	base/base	base-anvil	base-std
Beryl	pass	616	0	13	bf6113a3	6d744e03	4658f1b7
Cobalt	failure	596	250	14	bf6113a3	ae7557c4	3f899009

View run

[github-actions]

Caution

This PR may regress performance. 2 benchmark(s) slower by more than 10% beyond the noise band: batch_transaction_encoding/temporary_frame_buffers (+48.1%), execution/Insertion - 65,536 nodes (+20.7%).

Benchmark results (advisory)

Median time on the PR head versus the base branch, measured on the same host. Wall-clock, so a change is only flagged when it clears ±10% and the confidence intervals do not overlap. Only benchmarks past the ±10% threshold (plus new or dropped ones) are listed. This check never blocks a merge.

Benchmark	Base	Head	Δ median
batch_transaction_encoding/temporary_frame_buffers	254.90 µs	377.46 µs	+48.1% ⚠️ slower
execution/Insertion - 65,536 nodes	30.25 ms	36.52 ms	+20.7% ⚠️ slower
execution/Open 1024 nodes - 4096 nodes	37.79 µs	46.17 µs	+22.2% · within noise
execution/Open 1024 nodes - 65,536 nodes	72.18 µs	44.95 µs	-37.7% ✅ faster
tx_selection_parkable_payload/transactions/10000	6.81 ms	6.09 ms	-10.6% ✅ faster
tx_selection_predicate_rescan/transactions=10000_predicate_transactions=1000_predicates=1_stat	8.50 ms	7.28 ms	-14.4% ✅ faster
tx_selection_predicate_rescan/transactions=10000_predicate_transactions=1000_predicates=8_stat	9.04 ms	7.57 ms	-16.4% ✅ faster
tx_selection_predicate_rescan/transactions=10000_predicate_transactions=100_predicates=1_state	7.45 ms	6.69 ms	-10.1% ✅ faster
tx_selection_predicate_rescan/transactions=10000_predicate_transactions=100_predicates=8_state	7.46 ms	6.63 ms	-11.1% ✅ faster
tx_selection_predicate_rescan/transactions=10000_predicate_transactions=100_predicates=8_state_2	7.61 ms	6.68 ms	-12.2% ✅ faster
tx_selection_predicate_rescan/transactions=10000_predicate_transactions=10_predicates=1_state=	7.35 ms	6.53 ms	-11.2% ✅ faster
tx_selection_predicate_rescan/transactions=10000_predicate_transactions=10_predicates=8_state=	7.59 ms	6.51 ms	-14.3% ✅ faster

37 benchmark(s) within ±10% omitted.

View run · Re-run benchmarks