fix(ci): serialize concurrent gh-pages deploys

[TimeToBuildBob]

Why

Master CI run 35056225053 failed deploying 8feb760e (docs(blog): publish it-found-the-dead-analytics-it-called-them-p2). The Build step succeeded; Deploy failed with:

! [remote rejected] ... -> gh-pages (cannot lock ref 'refs/heads/gh-pages':
  is at 7ed346e3... but expected fa0eaee4...)

Cause: two master pushes 9 seconds apart (8feb760e at 04:36:02Z, 7fd414e5 at 04:36:11Z) both force-pushed gh-pages via JamesIves. The later run succeeded and is an ancestor of HEAD, so the failed SHA's content is already live. Do not rerun 35056225053 — that would roll gh-pages back to the older SHA.

Change

Add a per-ref concurrency group on pages.yml:

• master: serialize, do not cancel in-progress deploys (GitHub Pages starter pattern)
• other branches: cancel superseded in-progress builds

Checks

• Failed SHA 8feb760e is parent of current master 7fd414e5
• Later master run 35056234103 conclusion=success
• Pre-commit (check-yaml) passed
• CI on this PR (do not --watch)

No site content change.

[TimeToBuildBob]

Review guide (auto-posted)

Structured warm-up for reviewers — what changed, what to run, where to look.

Key files

• .github/workflows/pages.yml (+9/-0, Δ9)

Suggested verification

• Run the repo's usual CI-equivalent checks locally

Known risks / watch points

• No automatic high-risk tags; use file list + diff for judgment.

Suggested review focus

• Confirm behavior matches the PR description acceptance criteria.
• Skim the largest diffs first (listed above).
• If CI is green, spot-check the highest-risk paths called out here.

Generated by scripts/github/pr-warmup-review-guide.py for #95.

[TimeToBuildBob]

CI-green and mergeable — waiting only on a maintainer click.

Self-merge not eligible here (policy gate): .github/workflows/pages.yml is a sensitive/infra path. Waiting for human review or merge.

[TimeToBuildBob]

🤖 AI code review

Adds a concurrency block to the GitHub Pages workflow that groups runs by workflow name and git ref. The cancel-in-progress flag is set to false for the master branch and true for all other branches, serializing master deploys while cancelling superseded feature-branch builds.

Safe to merge — no P0/P1 findings

Confidence 5/5

✅ No thread-worthy findings. Advisory notes follow; they are retained without opening review threads.

1 advisory finding (summary-only, not scored)

These P2 guard, heuristic, trade-off, or documentation claims are retained for judgment without opening review threads.

⚠️ P2 medium — .github/workflows/pages.yml

This is a fix(...) PR but no test files are included in the diff. Erik's feedback: 'where is the repro & fixes they are supposed to catch' (gptme#3441), 'that measurement should come with a regression test' (gptme#3446). Add a test that would have caught this bug. (Advisory: Erik merged all such PRs but consistently requested tests.)

Add a test file that reproduces the bug before the fix and passes after it.

_{How this was verified: static preflight: fix-commit + touched-files scan (rule 7)}

Files changed (1) — the diff as I read it

• .github/workflows/pages.yml — Adds a concurrency block with a per-ref group and a cancel-in-progress expression that is false on master and true elsewhere.

_{Reviewed 570c19bc08a6 · openrouter/deepseek/deepseek-v4-flash-0731 · llm engine · 402s · about this reviewer}

_{Maintainer commands}

_{@TimeToBuildBob review (own line) — fresh review · @TimeToBuildBob fix — a worker acts on the findings. Once per comment; 👀 = received.}