track-work: issues filed by a subagent arrive unlabelled — the requirement does not survive delegation

[evanharmon1]

Invariant

track-work requires a new issue to be labelled — the label is what makes it
findable and triageable, and an unlabelled issue is invisible to every
label-scoped query the taxonomy exists to serve. That requirement must survive
delegation: an issue filed by a subagent needs the same labels as one filed
directly.

Current violation (observed 2026-08-11)

Two subagents running standardize-repo update mode filed follow-up issues from
confirmed Codex findings:

• ponderousdev/omator#320 — guard:codegen fails rather than skipping cleanly
  in a fresh worktree
• ponderousdev/omator#321 — Foreman's max_parallel=3 races on Playwright's
  fixed port

Both arrived with zero labels, and stayed that way until a retrospective
caught them. Both were good issues — reproducible, correctly scoped, worth
fixing — and both were unfindable by layer:, domain:, or bug queries.

The repo was not missing the vocabulary: setup-github-labels.sh had been run,
and all 71 labels existed. Nothing applied them.

This is the same root cause as #429 — a brief handed to a subagent carries the
task but not the skill's surrounding obligations, and the subagent does what the
brief says. The orchestrator's brief said "file follow-ups for confirmed
findings" and said nothing about labelling, so nothing was labelled.

Worth separating from #429 all the same: that issue's remedy is about the
shepherd stage and CI polling, and its acceptance criteria have no natural place
for issue hygiene. Folding this in would bury it.

Verify

# Any issue filed during a delegated run, checked for labels:
gh issue list --repo <owner/repo> --state all --limit 50 \
  --json number,title,labels \
  --jq '.[] | select((.labels | length) == 0) | "#\(.number) \(.title)"'

Expected on a repo where a subagent has filed follow-ups: unlabelled issues that
the maintainer never chose to leave unlabelled.

Acceptance criteria

• Guidance states that an issue filed by a subagent carries the same
  labelling requirement as one filed directly, and that a brief delegating
  issue-filing must say so.
• The requirement names the repo's actual taxonomy axes (layer:,
  domain:, plus type labels) rather than "label it appropriately".
• A subagent that cannot determine a label reports the issue number back for
  classification instead of leaving it bare.

Related: #429 (same root cause — briefs truncate the skill's requirements).

Found while running standardize-repo update mode via subagents on
ponderousdev/omator.