Marcos Hernanz 4d36801fdb Fix intercepted route params after Proxy rewrites (#97953) ...

## What?

Preserve the final internal rewrite pathname in the RSC response when an
earlier Proxy rewrite has already populated the rewritten-path header.

This also adds an end-to-end regression assertion for a dynamic
interception route behind a locale-injecting middleware rewrite.

## Why?

The route resolver set the final marker-bearing pathname directly on the
response, but router-server later reapplied the accumulated Proxy
response headers. That restored the earlier markerless pathname. The
client then parsed an intercepted dynamic param against that stale path
and removed three real characters from the value.

## How?

Mirror the final internal rewrite pathname into the accumulated
response-header map. When router-server applies that map after route
resolution, the last rewrite remains authoritative.

Fixes #97939

## Tests

- Production interception regression suite: 4/4 passed
- Development interception regression suite: 4/4 passed
- Related production rewrite/interception suites: 43/43 passed
- Next package build, targeted ESLint, Prettier, and git diff checks
passed

2026-08-28 15:50:12 -07:00

..

app

…

interception-dynamic-segment-middleware.test.ts

Fix intercepted route params after Proxy rewrites (#97953)

2026-08-28 15:50:12 -07:00

middleware.ts

…

next.config.js

…