For small sites a generated sitemap is overkill and a hand-written one rots. What's missing is a middle path: a form that guarantees valid XML with sane changefreq / priority values.

SitemapEditor edits a flat URL set — loc, lastmod, changefreq, priority per entry — with validateSitemap catching malformed locs and out-of-range priorities before they ship.

Controlled SitemapModel, preview beside it, persist. For dynamic routes keep generating server-side; this editor is for the curated set (the sandbox admin combines both).