test(evm): cap child_process.exec in lib.js to surface stalled commands

[wen-coding]

Summary

execCommand in contracts/test/lib.js wraps child_process.exec with no timeout. The Autobahn EVM integration matrix has hit multiple 30‑minute job timeouts where the hardhat process went silent at a test boundary, with the orphan‑process listing at cleanup consistently showing a stalled docker exec ... seid ... child still alive. The job then consumed its entire wall‑clock budget instead of surfacing a useful error.

This caps execCommand with a configurable timeout (default 60s, SIGKILL). On expiry, the rejection includes the offending command so the next occurrence is a 60s actionable error instead of a 30‑minute mystery. Override via EXEC_TIMEOUT_MS for tests that legitimately need longer.

Observed hang pattern (7 occurrences in 3 days)

Date (UTC)	Run	Affected Autobahn matrix job	Branch
05‑28 23:48	26608835541	EVM Interoperability	chore branch
05‑29 00:06	26609440164	EVM Interoperability	chore branch
05‑29 06:00	26620669539	EVM Interoperability	chore branch
05‑29 14:19	26642258916	EVM Interoperability	merge_queue #3506
05‑29 16:22	26648904362	EVM Interoperability	main push
05‑29 16:29	26648905384	EVM Interoperability	merge_queue #3511
05‑31 01:00	26699345153	EVM Module	PR #3525

Each ran for exactly ~30 minutes (job timeout). Investigation of one of the artifacts (26648905384): validators were perfectly healthy (continuing to produce blocks) the whole time, no test‑sender activity reached them during the silence — i.e., the hardhat process was alive but never sent another RPC, consistent with a stalled child process here.

Trade-off

• Healthy docker exec calls in the suite complete in ~100–200ms; 60s is comfortably above the worst observed normal case.
• If a specific test legitimately needs longer (e.g. genesis bootstrap), EXEC_TIMEOUT_MS overrides per-invocation.

Test plan

• CI: full integration matrix passes (60s is well above normal).
• The next time this stall pattern hits, the failing job will report a 60s execCommand timed out … <command> error instead of a 30‑min cancel — that error itself becomes the diagnostic.

🤖 Generated with Claude Code

[cursor]

PR Summary

Low Risk
Test-only change to integration helper timeouts; no production auth, chain, or runtime behavior.

Overview
Adds a 60s default wall-clock cap (override via EXEC_TIMEOUT_MS) on child_process.exec in execCommand, with SIGKILL on expiry, so stalled docker exec … seid … calls fail fast with a message that includes the command instead of hanging until the CI job hits ~30 minutes.

Timeout failures are detected only when Node reports error.killed and error.code is unset, so ERR_CHILD_PROCESS_STDIO_MAXBUFFER and external kills are not mislabeled as timeouts.

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[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Jun 2, 2026, 8:16 PM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.30%. Comparing base (1878cfa) to head (8ec7aa0).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3526      +/-   ##
==========================================
- Coverage   59.10%   58.30%   -0.80%     
==========================================
  Files        2213     2140      -73     
  Lines      182814   174318    -8496     
==========================================
- Hits       108046   101633    -6413     
+ Misses      65038    63664    -1374     
+ Partials     9730     9021     -709     

Flag	Coverage Δ
sei-db	70.41% <ø> (ø)
sei-db-state-db	?

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