WA-29949: Reduce PR review-label workflow costs

[Oxxyg33n]

Summary

Replace daily/manual full-PR scans and the selector/matrix jobs with monorepo's single event-driven job. Cancel superseded runs per PR, use trusted default-branch source, and preserve this repository's approval threshold. Update affected tests and usage instructions.

Task: WA-29949. Stale-PR automation and branch protection are unchanged. Monorepo reference: https://github.com/wallester/monorepo/blob/main/.github/workflows/pull-request-review-labels.yml

Validation

• node --test github-actions/pr-review-labeler/action.test.cjs: 34/34 passed (baseline 32/32). Actionlint v1.7.12 passed; YAML parsed; workflow matches monorepo except the preserved repository approval threshold.
• Full scoped diff reviewed for behavior, security, permissions and repository scope. No blocking findings found.
• Whitespace and published-file scope checks passed locally; published content is read back after creation.
• Automation scope: not applicable — development PR-maintenance tooling only; no application, release pipeline, or deployed service behavior changes.
• Application/Automation suites not run because they do not exercise this workflow-only change.

Risk and rollback

Inactive PRs and missed or read-only fork/Dependabot review events no longer receive periodic reconciliation. Matching monorepo also removes the explicit timeout and fork-review skip guard; GitHub token restrictions still apply. Labels are advisory; required reviews remain enforced by GitHub. Revert this commit to restore the previous workflow. Live event execution and savings require post-merge verification; this Draft PR does not enable the savings by itself.

[Oxxyg33n]

@Oxxyg3n test delta for WA-29949:

• Unit tests: added 5, changed 0, deleted 3. Each scenario counts once; removed scenarios cover the removed selector/scan behavior.
• Automation tests: not applicable — development PR-maintenance tooling only.
• Coverage impact: not measured as a line percentage because changed behavior is YAML configuration; embedded action logic is unchanged. Focused scenarios: 32 before -> 34 after, all passing.
• Local verification: node --test github-actions/pr-review-labeler/action.test.cjs: 34/34 passed (baseline 32/32). Actionlint v1.7.12 passed; YAML parsed; workflow matches monorepo except the preserved repository approval threshold.
• Local Automation verification: not applicable — no deployed service or release behavior changes.
• Automation test gap: not applicable.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-30T15:21:50.225293Z	ec0b6df	Draft marked ready

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