Add reusable Codex workflow templates

[haasonsaas]

Summary

• add org workflow templates for Codex PR review, CI triage, post-merge verification, and label churn audits
• add copyable Codex prompts for PR review, CI failures, label churn, local traffic, and post-merge checks
• document downstream adoption and OPENAI_API_KEY expectations

Test Plan

• ruby -e 'require "yaml"; ARGV.each { |f| YAML.load_file(f); puts "ok #{f}" }' .github/workflow-templates/.yml .github/workflows/.yml\n- ruby -e 'require "json"; ARGV.each { |f| JSON.parse(File.read(f)); puts "ok #{f}" }' .github/workflow-templates/.properties.json\n- ruby -Itest -e 'ARGV.each { |path| require "./#{path}" }' test/_test.rb\n- git diff --check

[cursor]

PR Summary

Medium Risk
Adds new GitHub Actions workflows that can post comments and, in the CI triage lane, write to the repo workspace; misconfiguration could create noisy automation or unintended write access, though changes are isolated to workflow templates and docs.

Overview
Adds new Codex prompt playbooks under .github/codex/prompts/ for PR review, CI failure triage, post-merge verification, label-churn audits, and local traffic/tracing investigations.

Introduces four new workflow templates under .github/workflow-templates/ that run openai/codex-action@v1 to (1) comment automated PR review findings, (2) capture failed run evidence and optionally comment a triage summary, (3) periodically or manually summarize default-branch health, and (4) audit label churn by collecting issue events and label-related workflow references.

Updates README.md with downstream adoption instructions and the required OPENAI_API_KEY secret expectation.

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