D827 — A links section ends at the next heading of any level, and its repair keeps a heading the template requires

Decision. The trailing links section ends at the first heading of any level after its own: a ### under ## Links is not part of it. Both link checks (duplicate_link, bare_link_list) and the repair read that one boundary (locateLinksSection). When duplicate_link or reciprocal_link_item empties the section, its heading goes (D307) unless a deeper heading follows (it still has children) or the page's template requires that H2 (by name or alias, and not among the template's optional sections): the repair leaves an empty heading instead of trading duplicate_link for template_section_missing. The two messages say that a line of prose is enough to keep a links section. Amends D287 and D307.

Why. A ### after ## Links is, in practice, a heading demoted from ## to get out of template_extra_section: prose, not links. Under the old boundary (same or higher level) its links counted for both checks, and the repair could drop a list line inside it as a "duplicate" — a destructive false positive. The boundary lived twice, in linksSection and in ReplaceLinkItem, each with its own regexp; one function now serves both so they cannot drift. Keeping a required heading costs an empty section on a page, which no check flags (only empty_concept exists); dropping it costs a finding the next lint reports. When the section is emptied but ### children follow, dropping its heading would re-parent them under the previous ##, so the heading stays.

Alternatives rejected. - Keep "same or higher level" and document it: it keeps the false positives and the destructive repair. - Sub-headings directly under the links heading are link groups, deeper ones are not: less predictable and harder to put in a message; no template or demo page groups its links under ###. - Never drop a links heading in the repair: the empty heading is noise on pages whose template does not ask for it. - Decide from the page's map alone: the template is what names the required H2s; the map only says which templates it accepts.

Consequences. A ### list under a links heading is text: its links are checked against the section's items and it is never edited by the repair. A page whose template requires the links section may carry it empty after a repair; a line of prose under it is enough, and nothing asks for a list. DropLinkItem and ReplaceLinkItem take a HeadingRequired; a caller that knows the page's template passes TemplateRequiresHeading, a nil one requires nothing.