feat(bin): replace chrome-devtools-axi with a real browser-verification helper

[yagakeerthikiran]

Summary

chrome-devtools-axi was reporting success while not doing the work: screenshot: /tmp/shot.png while writing no file, and Required at pageId for snapshot/eval right after a successful-looking open. This replaces it in firstmate's documented workflow with bin/fm-verify-page.sh, a real-browser verification helper built on playwright-core, and records two unrelated no-mistakes defects hit the same night so the next session doesn't have to rediscover them.

What bin/fm-verify-page.sh does

bin/fm-verify-page.sh <url> [--screenshot <path>] [--timeout <ms>] [--wait-until <state>] [--text-max <n>]

Returns one JSON object on success (url, final_url, status, title, text, screenshot); exits non-zero with the real error on stderr for any failure. The single hard requirement it's built around: it must never report success for something it didn't do. A screenshot path is stat'd for existence and non-zero size before it's ever mentioned in the success output. If chromium can't start, that's a loud failure, not a silent downgrade - including a no-root, apt-get-download + dpkg-deb self-repair for this sandbox's missing libnspr4/libnss3, which itself fails loudly if it can't fix things.

Failure-mode evidence (not just the happy path)

From tests/fm-verify-page.test.sh (hermetic, local HTTP server, no internet dependency) and manual runs this session:

• Connection-refused URL → non-zero exit, fm-verify-page: page.goto: net::ERR_... on stderr, no "status": 200 anywhere in the output.
• Browser executable missing (PLAYWRIGHT_BROWSERS_PATH pointed at an empty dir) → non-zero exit, fm-verify-page: browserType.launch: Executable doesn't exist at ... on stderr.
• playwright-core dependency not installed at all → non-zero exit, fm-verify-page: playwright-core is not installed (install: npm install --prefix <path>) on stderr.
• Real page (both the hermetic test server and, per the captain's own manual run tonight, live drivelog.com.au) → real 200, real rendered title, real rendered text, and a verified non-empty screenshot (386KB on the live site).

None of the failure cases above ever wrote a screenshot file or printed a success line - the exact opposite of the chrome-devtools-axi behavior this replaces.

Reference sites repointed (chrome-devtools-axi → bin/fm-verify-page.sh)

1. AGENTS.md (session-start tool line, section 3)
2. bin/fm-brief.sh (both the scout and ship brief scaffolds)
3. bin/fm-bootstrap.sh (dropped from COMMON_TOOLS required-tool detection and from install_cmd)

docs/configuration.md's "universal toolchain" description was also updated for consistency with bin/fm-bootstrap.sh (one-owner rule) since it described the same list. chrome-devtools-axi itself is untouched and still usable by hand - only its place in the documented workflow is removed.

Where the two no-mistakes defects are recorded

docs/known-tool-defects.md (new), with a one-line pointer from AGENTS.md section 7 "Validate":

1. CI-polling blindness - the pipeline's own ci step repeated warning: could not check CI: gh pr checks: exit status 1 for 14+ minutes on PR fix: recover safe fleet sync drift #111 while gh pr checks 111 / gh-axi pr checks 111 both succeeded by hand at the same moment.
2. Custody deadlock - on branch fm/dl-whatsapp-cloud-api, a cancelled run left gate-ref and preserved-pipeline-head pointing at different commits; both no-mistakes axi sync --recover and --recover --keep-local refused identically (confirmed inert - no refs/files changed), and no-mistakes axi run then refused to start because the previous run's custody wasn't recovered - a closed loop with no documented exit at this version.

Both are external-tool defects, out of scope to repair here; the doc records exact commands/output and the workaround used for each.

Test plan

• tests/fm-verify-page.test.sh - real page returns 200 + rendered title/text, screenshot written and non-empty, bad URL fails loudly, unstartable browser fails loudly (all pass locally)
• bin/fm-lint.sh (shellcheck + actionlint) clean on the full branch diff
• bin/fm-doc-audience-check.sh clean (new doc registered, owner pointer present)
• Manual verification against a live production site (drivelog.com.au) and a non-existent host, by the captain

Draft PR, ready to merge once green - captain merges.