ci: remove Node.js 16 from CI matrix (EOL Sep 2023)

[Justus-at-Tazama]

Summary

The node.js.yml build job currently runs a matrix across Node.js [16, 20]. Node.js 16 reached end-of-life in September 2023 and should be removed.

The lint and test jobs already use [20] only — this only affects build.

Change

File: .github/workflows/node.js.yml

# Before
strategy:
  matrix:
    node-version: [16, 20]

# After
strategy:
  matrix:
    node-version: [20]

Scope

node.js.yml is explicitly excluded from the sync-workflows.yml sync (to preserve per-repo benchmark customisations). After merging the canonical change here, all 35 downstream frmscoe/rule-* repos must be updated individually via script (see implementation plan in the comments).

Acceptance Criteria

• frmscoe/workflows canonical node.js.yml has node-version: [20] only in the build job
• All active frmscoe rule repos (rule-001 through rule-091) have node-version: [20] only in node.js.yml

Related

• Parallel track: tazama-lf/workflows#23 (Track A — additional changes for tazama-lf service repos)

[Justus-at-Tazama]

Implementation Plan — Track B (frmscoe/workflows)

Full plan including Track A: C:\DevTools\GitHub\-Claude-docs\update-workflows.md

---

Change

File: .github/workflows/node.js.yml, build job only

# Before (lint and test jobs already use [20])
strategy:
  matrix:
    node-version: [16, 20]

# After
strategy:
  matrix:
    node-version: [20]

---

Execution Steps

B1 — Create feature branch

gh repo clone frmscoe/workflows
cd workflows
git checkout dev && git pull
git checkout -b fix/remove-node-16

B2 — Apply change to node.js.yml

Change [16, 20] to [20] in the build job strategy.matrix.node-version.

B3 — PR to dev

git add .github/workflows/node.js.yml
git commit -S -m "ci: remove Node.js 16 from CI matrix (EOL Sep 2023)"
git push origin fix/remove-node-16
gh pr create --base dev --title "ci: remove Node.js 16 from CI matrix"

B4 — Manual node.js.yml update for all frmscoe rule repos

node.js.yml is explicitly excluded from sync-workflows.yml (to preserve per-repo benchmark customisations). All 35 rule repos need direct PRs.

Before running: confirm local clones at C:\DevTools\GitHub\rule-* are tracking frmscoe remotes:

git -C C:\DevTools\GitHub\rule-001 remote -v
# should show github.com/frmscoe/rule-001

$repos = @(
    "rule-001","rule-002","rule-003","rule-004","rule-006","rule-007","rule-008",
    "rule-010","rule-011","rule-016","rule-017","rule-018","rule-020","rule-021",
    "rule-024","rule-025","rule-026","rule-027","rule-028","rule-030","rule-044",
    "rule-045","rule-048","rule-054","rule-063","rule-074","rule-075","rule-076",
    "rule-078","rule-083","rule-084","rule-090","rule-091"
)

foreach ($repo in $repos) {
    $path = "C:\DevTools\GitHub\$repo"
    $file = "$path\.github\workflows\node.js.yml"
    if (-not (Test-Path $file)) { Write-Host "[$repo] no node.js.yml - skip"; continue }
    $content = Get-Content $file -Raw
    if ($content -notmatch '\[16,\s*20\]') { Write-Host "[$repo] already node 20 only - skip"; continue }
    Push-Location $path
    git checkout dev; git pull origin dev
    git checkout -b fix/remove-node-16 2>&1 | Out-Null
    $content = $content -replace '\[16,\s*20\]', '[20]'
    Set-Content $file $content -NoNewline
    git add ".github/workflows/node.js.yml"
    git commit -S -m "ci: remove Node.js 16 from CI matrix (EOL Sep 2023)"
    git push origin fix/remove-node-16 --no-verify
    gh pr create --base dev --title "ci: remove Node.js 16 from CI matrix" `
        --body "Node.js 16 EOL Sep 2023. lint and test jobs already use Node 20 only. Removes 16 from build matrix."
    Pop-Location
    Write-Host "[$repo] done"
}

B5 — Merge and clean up

1. Merge the frmscoe/workflows PR (Step B3)
2. Batch-approve and merge all fix/remove-node-16 PRs from Step B4

---

Related

• Track A (parallel): tazama-lf/workflows#23 — dynamic Docker tag, Node 16 removal, sync URL fix, and missing repo additions for tazama-lf service repos