fetchPageFile now rejects text/html responses so servers with SPA routing
(e.g. Cloudflare Pages with /* /index.html 200) no longer trick the renderer
into treating a fallback index.html as a found markdown file. Category-variant
pages (page.current.md with no plain page.md) now fall through correctly to
their variant URL.
mdcms build now writes a self-unregistering service-worker.js when pwa: no,
evicting any stale caching worker left over from a previous pwa: yes build.
manifest.json is also removed when pwa: no.
https://claude.ai/code/session_01Xs5GyREFhjWxhS1UhW2wA8
A YAML parse error in config.yml (e.g. a stray tab character) caused
read_config to swallow the exception and return {}, disabling categories
and producing a broken nav.yml with no variants fields and wrong filenames.
read_config now raises ClickException on both OSError and YAMLError.
Documented in docs/knownbugs.md and docs/unreleased.md.
https://claude.ai/code/session_01Xs5GyREFhjWxhS1UhW2wA8
