Merge from template editor branch, add preheader

Editor assessment

The 'wip' scope is a workflow flag, not a codebase section, so it fails scope semantics, and 'merge from template editor branch' is process narration that tells readers about git plumbing rather than the product change, which is added preheader support. Feat is right for that change. No body separates the two facts or explains what a preheader does for recipients or where it is configured. Hygiene otherwise passable, short and period-free. The useful content is present but buried under process noise and a pseudo-scope, keeping the message mediocre.