GTR092 — Convert RST <help> to Markdown (opt-in command)

Contract: render-equivalence (proof by execution).

Claim

The conversion is kept only when provably render-equivalent.

Proof — by execution, per tool

Render the RST exactly as Galaxy’s server does (docutils html4css1) and the converted CommonMark exactly as Galaxy’s client does (markdown-it js-default, html:false); reduce both to a normalized semantic skeleton; accept iff equal (tier-1 rst_markdown, xml §24). Negative-controlled. Profile ≥ 24.2 XSD gate; never part of format/upgrade (it swaps the rendering engine by design — hence opt-in-command-only).