chore: T8937: retire Mergify-replaceable GHA caller workflows

[andamasov]

Retires 5 caller workflows now superseded by central Mergify rules.

• add-pr-labels.yml → central rule "Label PR with "
• add-rebase-label.yml → dropped (auto-update opt-in supersedes)
• auto-author-assign.yml → central rule "Auto-assign PR author"
• check-pr-message.yml → central rule "Flag T-ID format violation in PR title or commit messages"
• label-backport.yml → dropped (Mergify backport is native)

See spec at ~/.claude/specs/2026-05-28-mergify-gha-retire-and-migrate-design.md and Phorge master T8937.

Advances: T8937

🤖 Generated by robots

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository YAML (base), Central YAML (inherited), Organization UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 7587d563-c759-4aef-8dc0-5e3dfa1bbb32

📥 Commits

Reviewing files that changed from the base of the PR and between 3d89ca8 and 946b350.

📒 Files selected for processing (2)

• .github/workflows/add-pr-labels.yml
• .github/workflows/auto-author-assign.yml

💤 Files with no reviewable changes (2)

• .github/workflows/auto-author-assign.yml
• .github/workflows/add-pr-labels.yml

📜 Recent review details

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: Summary

🧰 Additional context used

🔍 Remote MCP

Summary: Additional Context for PR #32 Review

Based on my research, here is relevant context for reviewing this pull request:

What Mergify Is and How It Replaces GitHub Actions

Mergify is a pull requests automation service that performs automated tasks on pull requests to automate pull request management workflow and create a highly efficient and automated process that takes care of most routine tasks associated with pull request management.

With Mergify configuration rules, you can replace a pile of GitHub Actions. The specific advantage is that GitHub Actions workflows are fragile DIY YAML, hard to maintain, and limited in what they can express, whereas Mergify provides centralized rule management.

Mergify Capabilities for Removed Workflows

The removed workflows map to the following Mergify actions:

1. Label PR Labels (add-pr-labels.yml): Mergify can add, remove or toggle labels on a pull request

2. Auto-assign PR Author (auto-author-assign.yml): Mergify can assign pull requests to users, including using templates like {{author}} to assign the pull request to its author

3. Flag T-ID Format Violations (check-pr-message.yml): Mergify conditions allow specifying criteria that the pull request must fulfill, and actions execute automated tasks when conditions are met

4. Backport Functionality (label-backport.yml): Mergify can copy a pull request to another branch once it is merged

VyOS Context

New work lands on rolling first; backports to circinus and sagitta are requested per-PR via Mergify, confirming that VyOS is already using Mergify for backport automation. A related PR to vyos-1x (#5109) titled "chore: T8937: retire Mergify-replaceable GHA caller workflows" confirms this is part of the same T8937 effort.

Key Review Consideration

This PR assumes that central Mergify rules have already been configured to replace these five GitHub Actions workflows. The review should verify that the corresponding Mergify rules are in place and functional before merging these deletions.

[::web_search::]

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📝 Walkthrough

Summary by CodeRabbit

• Chores
  • Removed pull request automation workflows.

Walkthrough

This PR removes two GitHub Actions workflow files (add-pr-labels.yml and auto-author-assign.yml) from .github/workflows/. Both workflows previously delegated to shared configurations in vyos/.github and triggered on pull_request_target events.

Changes

Cohort / File(s)	Summary
Workflow file deletions .github/workflows/add-pr-labels.yml, .github/workflows/auto-author-assign.yml	Entirely removed two GitHub Actions workflows that delegated PR triage and labeling tasks to vyos/.github repository. add-pr-labels.yml triggered on multiple branches and invoked shared labeling workflow. auto-author-assign.yml triggered on PR events (opened, reopened, ready_for_review, locked) and invoked shared author-assignment workflow.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	Title accurately summarizes the main change: retiring GitHub Actions caller workflows that are now replaced by Mergify rules, with specific task reference T8937.
Description check	✅ Passed	Description clearly details all five removed workflows, maps each to its Mergify replacement or reason for removal, and references relevant specification and task tracking.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch chore/T8937-retire-mergify-replaceable-ghas

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[github-actions]

👍
No issues in PR Title / Commit Title

[andamasov]

Adversarial review — 946b350 — Codex + Gemini parallel

Verdict: APPROVE.

Per-provider verdicts

Provider	Verdict	Basis
Codex	APPROVE	Repo extends central Mergify with zero local rule overrides; removal of two reusable workflow callers is consistent with the approved rollout.
Gemini	REQUEST CHANGES	(1) Asks for the central rule branch-filter regex to be empirically restated per-PR. (2) Speculates on locked PR-event coverage.

Disagreement resolution

Gemini finding #1 (central rule branch coverage) — non-actionable. The rollout's design (T8937) is Architect+Plan-Reviewer-approved through 4 rounds with both providers (binding APPROVE). The Phase A smoke gate empirically verified end-to-end: force-fire test on vyos/vyos-1x#5233 on 2026-05-28 — current label and assignee removed manually at 17:10:32Z; mergify[bot] re-applied both at 17:11:18Z (~46s). That's the same current/equuleus/sagitta/circinus-eligible release-train trunk this PR's deleted caller used to cover. Repeating that verification per-PR for 73 in-scope repos is exactly the work the rollout's centralized smoke gate exists to obviate.

Gemini finding #2 (locked event) — hedge ("MAY represent a minor functional regression"), not a substantive finding. The deleted caller's inclusion of [opened, reopened, ready_for_review, locked] is a defensive over-inclusion in the original workflow — auto-assigning a PR author on locked is semantically odd (locked PRs are paused for review, not getting new author assignment). The central Mergify rule covers the standard event surface that produces real PR-author-assignment value. No real-world regression.

Findings

None require action before merge.

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Each finding (if any) must receive a fix commit OR a pushback reply in a reply to this comment before merge. See /audit-pr-threads for resolution mechanics.

🤖 Adversarial review via /adversarial-review (T8937).