next.js

0e6ab3f5 - [Prefetch Inlining] Generate size-based hints on server (#90891)

[Prefetch Inlining] Generate size-based hints on server (#90891) Part 1 of 2. This commit adds the server-side infrastructure for size-based segment bundling but does not change any observable behavior. The client-side changes that actually consume bundled responses are in the next commit. At build time, a measurement pass renders each segment's prefetch response, measures its gzip size, and decides which segments should be bundled together vs fetched separately. The decisions are persisted to a manifest and embedded into the route tree prefetch response so the client can act on them. The decisions are computed once at build and remain fixed for the lifetime of the deployment. They are not recomputed during ISR/revalidation — if they could change, the client would need to re-fetch the route tree after every revalidation, defeating the purpose of caching it independently. Refer to the next commit for a full description of the design and motivation. ## Config experimental.prefetchInlining accepts either a boolean or an object with threshold overrides (maxSize, maxBundleSize). When true, the default thresholds are used (2KB per-segment, 10KB total budget). The auto behavior will eventually become the default. The config will remain available for overriding thresholds.