Removes `continue-on-error: true` from `.github/workflows/visual-diff.yml`'s
`Capture screenshots (PR)` step. Visual drift is now a real merge gate
on UI-touching PRs.
Brief 2/2 of the `harden-visual-diff-gate` convoy. PR #138 shipped the
seed workflow (Brief 1); PR #139 (`54495fe`) landed the fresh Linux
baseline regenerated against post-glass-redesign main on CT 111. With a
known-good baseline committed, the gate can flip without false-failing
every UI-touching PR.
## What changes
- `.github/workflows/visual-diff.yml` — drop the
`continue-on-error: true` flag; add an inline rationale block linking
to the convoy + the operator runbook for both intentional changes
(dispatch seed workflow → manually open PR → merge → re-run) and
unintentional regressions (inspect artifact diff → fix → push).
- `.github/workflows/ci.yml` — add 9th `forbidden-patterns` check that
greps `visual-diff.yml` for `^\s*continue-on-error:\s*true` and fails
the build if it returns. Risk #3 of the convoy made concrete: prevents
silent re-introduction via template revert. Scoped narrowly to that
one file; other workflows (`seed-visual-baselines.yml`'s PR-open
step, etc.) legitimately use the flag. Job name bumped from
"Forbidden patterns (8 checks)" → "(9 checks)". All `Check N/8`
group labels renumbered to `N/9`.
- `AGENTS.md` — § Testing § Visual baselines rewritten to drop the
"Known staleness as of 2026-06-12" callout (resolved by PR #139);
§ Testing § Screenshot diff rewritten to lead with "hard merge gate",
document the intentional-change runbook, reference the new ci.yml
check, and explicitly mention the org-setting caveat for the seed
workflow's auto-PR step.
- `tests/visual/homepage.spec.ts` — module docblock rewritten to match
the AGENTS.md runbook: drops the "advisory, not gating" language;
promotes the seed-visual-baselines workflow as the primary
re-seeding path; demotes the Playwright Docker image to the offline
fallback.
- `.github/workflows/seed-visual-baselines.yml` — patches the
`peter-evans/create-pull-request@v6` PR-open failure case discovered
during Brief 1's first dispatch (run 27454132468). The PR-open step
is now `continue-on-error: true` (narrowly scoped, with an inline
rationale callout distinguishing it from the just-removed
`visual-diff.yml` flag — that one silently hid real UI regressions;
this one fronts a known org-level "Allow GitHub Actions to create
and approve pull requests" limitation with a loud failure notice).
New steps disambiguate the three possible outcomes (no-changes /
pr-opened / branch-pushed-pr-blocked) via a `git ls-remote` check on
the bot branch and exit non-zero on the blocked-PR case so the
workflow run shows red and the operator gets the exact `gh pr create`
command in the run logs.
- `.convoys/harden-visual-diff-gate.md` — status: shipping; Step 2
marked SHIPPED; Decision D4 ratified (chose option C: accept org
setting, document manual `gh pr create` fallback). Inline links to
PR #139 + PR #140.
## Test plan
- [x] `npm run lint` — clean (1 pre-existing unrelated warning)
- [x] `npm run test:run` — 24 files / 118 tests pass
- [ ] CI on this PR: 9th forbidden-patterns check passes; visual-diff
job passes against the fresh baseline; convoy-metrics-gate passes
(2 new rows added by this commit)
- [ ] After merge: smoke test the 9th check by opening a throwaway PR
that re-adds `continue-on-error: true` to `visual-diff.yml`; confirm
it red-X's. (Skip if confident in the grep.)
## Convoy state
- Brief 1: SHIPPED (PR #138, `c100c5f`, 2026-06-13)
- Baseline refresh: SHIPPED (PR #139, `54495fe`, 2026-06-13)
- Brief 2 (this PR): shipping
- Convoy closeout: this PR's merge
Co-authored-by: Cursor <cursoragent@cursor.com>
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