The turbopack dev variant runs with TEST_ENV=dev-turbopack, which the
development check did not match, so the tags-absent assertions ran against
a dev render where the tags are fresh and kept.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Next.js computes a document's trace meta tags at the top of its prerender
function, inside the span it wraps the prerender in. Recognizing that span by
its attributes fails when the request is not sampled: the span is then
non-recording and has no attributes, so the propagator still wrote a
`sampled=0` tag into the cached shell, and every later visitor inherited the
negative decision. A span nested in the prerender would have passed the check
as well.

Mark the prerender on the OpenTelemetry context instead, through the tracer
provider the Node SDK registered, and have the propagator skip a marked
context. The mark is inherited by everything that runs inside the prerender
and exists whether or not the span records.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

… caller

Next.js starts its spans through `startActiveSpan`, which the tracer wrapper
marks on the context. A span started through `startSpan` and set on a context
by the caller takes a different path, so the wrapper remembers those spans and
the propagator checks the span on the context too.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

…flare

ISR pages revalidate inside a request of the Worker, where `withSentry` of
`@sentry/nextjs/cloudflare` registers its own tracer provider and propagator.
The guard only covered the setup of the Node SDK, so a shell prerendered in
the Worker got that request's trace. The Next.js integration now marks
prerenders on the tracer provider `@sentry/cloudflare` registered and its
propagator skips a marked context.

Also moves the changelog entry above the contributor line and fixes a test
comment that pointed to a file of the follow-up PR.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

The ISR shells of the e2e apps come from the build, where the SDK does not
run, so the tag assertions passed with or without the guard. A page with a
one second window makes the server prerender it again inside a request.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>