[Gitflow] Merge master into develop

…l build mode (#16410)

Next.js v15.3.0-canary.1 introduced a new approach to the two-phase
experimental build (--experimental-build-mode=compile then =generate)
that applies env inlining during generate build mode.
 
Why it breaks?
Our `withSentryConfig` still assumes a single “full” build and reruns
its Webpack instrumentation in both phases. During the generate step it
collides with Next.js’s new inliner (e.g. for assetPrefix), producing
malformed JS and build failures.

Root cause: Double application of build-time transforms—Sentry
inlines/reprocesses a bundle that Next.js’s generate mode is
simultaneously trying to finalize—leads to conflicting replacements and
syntax errors.

This PR is a quick workaround that patches our build script so that:
1. Compile phase (--experimental-build-mode=compile): Sentry’s
instrumentation runs as usual.
2. Generate phase (--experimental-build-mode=generate): We skip Sentry’s
build-time hooks entirely, letting Next.js handle inlining and
prerendering without collision.

This immediately prevents the build failures and defers full “generate”
work to Next.js’s own pipeline. I confirmed that source maps and error /
tracing still function as expected, BUT things might still occur as it's
still an experimental undocumented feature.

---------

Co-authored-by: Charly Gomez <charly.gomez@sentry.io>

Re-exports functionality from the `@sentry/react`. However, not
everything is exported as the react router exports would be confusing.

closes #16459

…ttpInstrumentation doesn't crash (#16473)

On Node > 22.10.0, when spans are off, the `SentryHttpInstrumentation`
attempts adding `sentry-trace` and `baggage` headers to requests. Due to
race-conditions, this can error in cases where the request was already
sent/finished prior to setting the headers.

This fix prevents this by wrapping the logic in a try/catch.

Fixes: #16438

meta(changelog): Update changelog for 9.26.0