Repo governance: label taxonomy, triage workflow, and PR lifecycle #690

Context

This umbrella issue tracks the work to establish a structured label taxonomy, define triage and PR lifecycle workflows, and migrate existing issues/PRs to the new system.

Since 0.41.0-incubating already passed IPMC vote, and the project has grown significantly, it was time to professionalize issue/PR management.

Current state

• All open issues and PRs use the new prefix/value taxonomy (kind/*, area/*, priority/*)
• 40 new labels created, 27 legacy labels deleted
• gsoc2026 renamed to gsoc, release-issues renamed to release
• Full triage completed: 21 stale/resolved issues closed

Label Taxonomy

Convention: prefix/value (scannable, filterable, consistent)

kind/ — What it is (required on every issue and PR)

area/ — Where in the codebase (at least 1 per issue/PR)

priority/ — How urgent (required after triage)

status/ — Where it is in the workflow

pr/ — PR workflow (PRs only)

lifecycle/ — Long-term issue management

Special labels (kept as-is)

Triage workflow

New issue opened
  → auto-apply: status/needs-triage
  → Triager adds: kind/* + area/* + priority/*
  → Triager removes: status/needs-triage
  → Triager adds: status/accepted

New PR opened
  → Triager adds: kind/* + area/*
  → If CI fails: pr/needs-rebase or comment
  → If reviewed and ready: pr/ready-to-merge
  → If 14 days without update after review: pr/stale → convert to draft
  → If 90 days without activity: lifecycle/stale → close with comment

Stale PR policy

PRs with review comments and no response for 14 days get pr/stale and are converted to draft. PRs with no activity for 90 days are closed with a comment inviting the author to reopen when ready. This keeps the open PR list honest and actionable.

Sub-issues

• chore: create new label taxonomy and remove old labels #691 Create new labels and delete unused ones
• chore: migrate open issues to new label taxonomy #692 Migrate all open issues to new taxonomy
• chore: migrate open PRs to new label taxonomy #693 Migrate all open PRs to new taxonomy
• chore: triage and close resolved issues #694 Triage and close resolved issues
• chore: define stale PR policy and clean up inactive PRs #695 Define stale PR policy and clean up inactive PRs
• chore: set up auto-labeling for new issues and PRs #696 Set up GitHub Actions for auto-labeling status/needs-triage
• chore: define issue assignment policy #709 Define issue assignment policy