The schema file lives at docs/function-classification-schema.md but is
not a published Starlight page, so a relative link resolves fine in the
manual source tree but breaks once copied into
docs/site/src/content/docs/ — starlight-links-validator failed CI's
build-docs job on it. Rewrite it as an absolute Gitea blob URL, the same
pattern _rewrite_repo_links already uses for CONTRIBUTING.md/LICENSE.