Each index route also emits a parent-level alias twin, projected over
the alias route so its relative links stay correct; llms.txt and the
docs now state the drop-trailing-slash convention exactly. Frontmatter
failures name their page, the twin pass refuses to overwrite existing
build files, the dev middleware documents the deliberate in-page
fetch() divergence, and the per-locale collection order moves to one
shared export. Refs #2846.
Append .md to any published route for the page as plain Markdown: the
build emits a raw-Markdown twin of every route (frontmatter dropped,
home bodies kept, images beside pages) plus a manifest-generated
llms.txt, the dev server serves both per request, and the post-build
gate fails when either is missing. Fixes#2846.
gengruilin