feat(labels): estate label tooling + auto-triage for new issues (#50)

Ships the canonical label set and the classifier that labels newly-filed
issues.

**Additive only** — never removes a label, never overrides a human's
classification, silent when unsure, never fails an issue.

Also adds this repo's two new workflows to
`.github/workflows/actions.lock` as `[]`. That lock is keyed by workflow
path and refuses any workflow it does not list — a `startup_failure`,
which produces **no check run** and is therefore silent. `gh
actions-lock` cannot add these: it records action *versions*, and both
workflows deliberately use none.

See `docs/LABELS.adoc` in hyperpolymath/.git-private-farm.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: hyperpolymath