docs: add Partial Prefetching adoption guide; cross-link from prefetching + Link API
Adds a new adoption guide for Partial Prefetching (the
'partialPrefetching' next.config flag) covering:
- What changes for <Link>: shell-only default, prefetch={true} to also
prefetch page content
- Adopting in a new project: partialPrefetching: true
- Adopting incrementally in an existing project: prefetch = 'partial'
per page, then flip the global flag
- Per-route eager prefetching with prefetch = 'unstable_eager'
Also updates four existing surfaces to cross-link the new guide and the
PPF behavior change:
- docs/01-app/02-guides/instant-navigation.mdx: cross-link from the
'Build the static shell' section and 'Next steps', plus drop the
stale unstable_disableValidation guidance now that the API is no
longer recommended.
- docs/01-app/02-guides/prefetching.mdx: callout near the top pointing
Cache Components readers at the adoption guide.
- docs/01-app/02-guides/runtime-prefetching.mdx: brief mention of
<Link prefetch={true}> in the App Shells section.
- docs/01-app/03-api-reference/02-components/link.mdx: callout under
the prefetch prop describing the PPF default change.