Workflow: how to keep an issue alive as a todo when it doesn't become a useful clean result

Goal

Decide the canonical workflow path for issues that reach status:awaiting-promotion (or earlier) where:

• The experiment ran or partially ran,
• The result isn't load-bearing enough to promote as clean-results:useful,
• BUT we don't want to abandon the question — there's a clear next step we want tracked.

The current options are not crisp:

1. Promote as clean-results:not-useful and create a separate status:proposed follow-up issue. Works, but conflates "explored framing isn't useful for the paper" with "experiment didn't yield interpretable results — we'd like to retry differently."
2. Close the issue (auto-archives) and reopen / file a new one later. Loses lineage and the partial work.
3. Set status:blocked. Wrong semantics — nothing is blocking it, we just don't have bandwidth or it needs a redesign.
4. Leave it parked at awaiting-promotion. Pollutes the column the user uses to triage promotion decisions.

Question

What is the canonical path? Candidates:

• (a) Use not-useful as the todo bucket. Document that not-useful doesn't mean "abandoned" — the live next-step is a fresh status:proposed follow-up that links back. Cheapest, no new mechanism.
• (b) New label status:parked-with-followup or a new project column. Explicitly distinguishes "experiment didn't produce a clean result, but we want to come back" from "promoted as not-useful." More mechanism, clearer semantics.
• (c) A todo/backlog label that lives orthogonally to the status state machine. The issue keeps its current status; the label flags "user wants to revisit."

Trigger / context

Surfaced while promoting #284 (Gaperon evolutionary trigger round-0 diagnostic) — a clean MODERATE-confidence negative result that earns useful, but the conversation raised the question for the broader case of issues where clean-result promotion isn't the right exit.

Acceptance

• Decision recorded in CLAUDE.md (or .claude/skills/promote-clean-result/SKILL.md if scoped to the promotion gate).
• If a new label / column is added, scripts/gh_project.py updated and the project board structure documented.
• The /promote-clean-result skill's "useful vs not-useful" decision tree updated to reference the new path.