[teamleaderleo]

Carry of #27674: fix latency scoreboard incomplete browser engine coverage.

Merged current feat-cmux-next into the original reviewed commits to resolve the conflict and force fresh checks/review. Original: #27674

Original purpose (#27674):

The latency scoreboard used to catch every browser launch error as an unstructured warning and continue. A partial Chromium/WebKit sweep could therefore look complete.

Performance

No perf numbers: this changes latency evidence reporting only; it does not alter measured latency or budgets.

Agent session: agent session

[github-actions]

cmux status _{(one comment, edited in place; each line is updated by the job that owns it)}

Review cef7293: HQ feed card · gallery before/after runs · checks

App of this head (app.zip, kept 1 day)

gh workflow run reload-build.yml -R manaflow-ai/cmux --ref feat-cmux-next -f tag=pr28156 -f ref=lane/carry-27674-latency -f platform=macos -f backend_mode=local

Passes: CI passes on cef72935c5.

CI passes on cef72935c5 (run 41168861527 attempt 1).

Written by scripts/ci/classify_failures.py (ci-failure-attribution.yml); signatures are its SIGNATURES table. A machine verdict is the runner's fault, not this PR's; yours means the failing file is one this PR changes, also red on main that main's latest full suite fails the same way, seen on other PRs that it failed on another pull request's run lately.

web and size checks: green

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4117757429001 (cbd1fc5db2)
• cmux NEXT nightly 1.0.0-nightly.4117797037301 (c9ae20d5c2)
• cmux NEXT nightly 1.0.0-nightly.4117948839501 (e43764d3e1)
• cmux NEXT nightly 1.0.0-nightly.4118042477101 (133d5a9bd7)
• cmux NEXT nightly 1.0.0-nightly.4118089936901 (7975c7a9e0)
• cmux NEXT nightly 1.0.0-nightly.4118163201202 (05730c30a0)
• cmux NEXT nightly 1.0.0-nightly.4118400110201 (c904112cd1)

[blacksmith-sh]

Found 72 test failures on Blacksmith runners:

Failures

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...and 62 more test failures. View all on Blacksmith

^{Need help on this PR? Tag @codesmith-bot with what you need.}

[teamleaderleo]

Review (independent Codex gpt-6.1-sol, high, via the review router; full diff from merge base 5be39f0 to this head): BLOCK at 27a7198.

[P1] webviews/scripts/latency/run.ts:149-162 - The module no longer exports parseOptions, evidenceErrors, or sampleIdle, and executes the entire benchmark during import. The existing latency-core-schema.test.ts therefore cannot load and the webview test suite fails. - Restore the exported API and main()/import.meta.main guard, or update all existing callers and tests.
[P2] webviews/scripts/latency/run.ts:85-90 - Server startup has no timeout and only matches the URL within each individual output chunk; a split or changed Vite banner leaves the promise pending until CI times out. - Buffer output across chunks, handle error/early exit, and enforce a startup timeout with cleanup.
[P2] webviews/scripts/latency/run.ts:186 - Page errors are reduced to console.warn, so runtime fixture failures no longer contribute to the run result and can be reported as passing measurements. - Record page errors as run/action failures and make them affect the exit status.

[teamleaderleo]

Review (independent Codex gpt-6.1-sol, high, via the review router; full diff from merge base 5be39f0 to this head): BLOCK at db2af6e.

[P1] webviews/scripts/latency/run.ts:299 - engineNames is undeclared, so TypeScript compilation fails (or a successful launch throws ReferenceError), preventing all latency measurements - replace with measuredEngines.push(engineName).

[teamleaderleo]

Review (independent Codex gpt-6.1-sol, high, via the review router; full diff from merge base 5be39f0 to this head): SHIP at 456faae.

No P1/P2 findings.

[teamleaderleo]

Owned by an agent session · session

[teamleaderleo]

Review (independent Codex gpt-6.1-sol, high, via the review router; full diff from merge base b828e44 to this head): SHIP at 5ae893d.

No P1/P2 findings.

[teamleaderleo]

Review (independent Codex gpt-6.1-sol, high, via the review router; full diff from merge base b828e44 to this head): SHIP at 8c60c5e.

No P1/P2 findings.

[teamleaderleo]

Review (independent Codex gpt-6.1-sol, high, via the review router; full diff from merge base 584b3f6 to this head): SHIP at cef7293.

No P1/P2 findings.