A Next.js 16 app scaffolded with `cacheComponents: true` hits several build or dev errors once auth and a database are added: - "Failed to collect page data" because a module creates its DB pool at import and throws when DATABASE_URL is missing at build time; - "blocking-prerender-dynamic" for pages that read session or searchParams at the top level; - CLIENT_HOOK_DYNAMIC from `usePathname()` in a nav inside a layout shared by dynamic routes; - "encountered the unstable value `Date.now()` while prerendering" coming from the auth/session helper. Separately, the dev server can keep serving a stale globals.css after a rewrite (theme tokens missing) until it is restarted.