next.js

be25b831 - docs: update adapter docs for routing, handlers, and PPR (#89849)

docs: update adapter docs for routing, handlers, and PPR (#89849) ## Summary - update `experimental.adapterPath` docs to match current `onBuildComplete` shape (`routing`, `buildId`, and latest output types) - document `@next/routing` usage and note its experimental status - add runtime entrypoint signature details for Node.js and Edge (`handler(..., ctx)`) - add a new PPR implementation section with markdown flow diagrams for shell/resume stream composition and `requestMeta.onCacheEntryV2` cache updates - link to `nextjs/adapter-vercel` as the reference adapter example