Phase 1: Org-wide PR template, label taxonomy, and reusable workflows

[bryanbeverly]

Summary

Phase 1 of a cross-repo PR labeling and hygiene rollout. Populates this repo with shared building blocks that consumer repos in the org will call.

What this PR adds:

File	Purpose
.github/PULL_REQUEST_TEMPLATE.md	Default PR template inherited by every repo without its own
labels.yml	Single source of truth for the 11-label taxonomy (size/*, risk/*, review/urgent, status/stale, complexity/high)
.github/workflows/pr-labeler-reusable.yml	Reusable workflow: applies size/risk/checkbox labels
.github/workflows/label-sync-reusable.yml	Reusable workflow: syncs labels.yml into a caller repo
.github/workflows/stale-reusable.yml	Reusable workflow: wraps actions/stale@v9 (14d stale, 16d close, exempts review/urgent and drafts)
.github/workflows/lint.yml	ruff (Python) + actionlint (workflow YAML)
.github/workflows/test-scripts.yml	Runs unit tests on PRs and pushes
.github/scripts/pr_labeler.py	Labeler logic: size buckets, Bugbot risk parsing, checkbox state
.github/scripts/label_sync.py	Label sync logic via `gh label create --force` (additive)
.github/scripts/test_pr_labeler.py	35 unit tests for labeler logic
README.md	Documents what lives here, perms model, how to add a label

Permissions model: No reusable workflow declares its own `permissions:` block — they inherit from callers. Each consumer caller declares the minimum its reusable needs (documented in README).

Versioning: Caller workflows reference these reusables at `@main`. Pushes to this branch immediately affect every consumer once they merge their callers in subsequent phases. Branch protection on `main` requires PR review.

Required follow-up after merge (manual UI step)

Set org default labels: `Organization settings > Repository defaults > Repository labels` → replace GitHub's defaults with the 11 labels from `labels.yml` so brand-new repos get them on day one. Existing repos are populated by the sync workflow in subsequent phases.

(No "enable Actions access" step is needed — this repo is public, so its reusable workflows are callable from anywhere by default.)

Test plan

• All 35 unit tests pass locally (size buckets, Bugbot risk regex incl. unmapped levels, three-state checkbox parsing, label reconciliation that doesn't strip manual labels)
• All YAML files parse cleanly
• `ruff check` and `ruff format --check` clean on all Python sources
• `actionlint` clean on all 5 workflow files
• Lint and test-scripts CI workflows run green on this PR

Made with Cursor

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Note

Medium Risk
Medium risk because it introduces reusable GitHub Actions and automation that can modify labels and stale/close PRs across consumer repos once adopted.

Overview
Adds org-wide GitHub tooling in this .github repo: a default PULL_REQUEST_TEMPLATE.md, a canonical labels.yml, and reusable workflows for label syncing, PR auto-labeling, and PR staleness handling.

Implements Python scripts to (1) sync labels into a target repo via gh label create --force (additive) and (2) compute/apply PR size/*, risk/* (from <!-- CURSOR_SUMMARY -->), and author-declared review/urgent / complexity/high labels from template checkboxes, with unit tests plus CI linting (ruff, actionlint) and script test coverage.

^{Reviewed by Cursor Bugbot for commit e55e76b. Bugbot is set up for automated code reviews on this repo. Configure here.}