Refresh the never-scaffold ADR against the post-#27 skill

[ckrough]

scriptorium/docs/decisions/never-scaffold-mode-trees.md describes a version of scriptorium/skills/docs/SKILL.md that no longer exists. PR #42 (closing #27) changed the skill's structure and grew it from 215 to 253 lines, and the ADR was outside that change's agreed file scope, so it was deliberately left alone.

Found by the /simplify reuse pass during #27. Filing it separately because an ADR that misdescribes the skill it governs is worse than no ADR: its own closing section routes future contributors to read it first.

What is stale

• Every line-number citation into SKILL.md is now wrong. The ADR cites lines 129, 136, 182, 184, and 186-190. Each was accurate against d393f87 and each now points at unrelated text.
• The Consequences section describes a structure that was removed. It states "The never-scaffold precondition appears twice in SKILL.md: once in the drafting checklist, once as its own named section." PR Specify file naming, frontmatter, and pre-emission checks for the docs skill #42 deleted ### Checklist before returning a draft and absorbed it into the nine-item ## Self-check before emitting. The precondition now appears in self-check item 2 and in the standalone ### Never-scaffold section under ## Place path.

Worth deciding while in here

### Never-scaffold sits under ## Place path, but after #27 it is enforced by a write-path gate (self-check item 2). The /simplify review flagged that placement as the reason the item needed an apologetic parenthetical, which was then removed. Either the section moves under ## Write path, or the ADR states why it stays where it is.

Acceptance Criteria

• Every SKILL.md line-number citation in the ADR resolves to the text it claims, or is replaced with a heading reference that does not rot on the next edit
• The Consequences section describes the current two locations of the never-scaffold precondition, not the removed drafting checklist
• The section-placement question above is either resolved by moving ### Never-scaffold, or answered in the ADR
• bash scripts/gates/structure.sh and claude plugin validate . both exit 0