Root cause (SPA mode, fallback: index.html): the SW precached build+files but
NEVER the shell HTML, so its navigation fallback `caches.match('/')` resolved to
nothing — any failed navigation fetch (transient WAN/CF blip) returned an empty
response → blank white screen.
Fix: precache `/` on install, and on every successful navigation keep the
freshest *real 200 text/html* response as the cached shell; on a failed fetch,
serve that cached shell instead of blank. Also expanded the server-owned path
exclusions (the SW now passes through /docs, /openapi.json, /healthz, /today,
/sitemap.xml in addition to /api/ and /a/) so it never caches non-SPA responses
as the shell.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
thejayman77
c7e00e7fdc