feat(remix): Add Remix 3 browser SDK with a bundled client entry (#24802)

Remix 3 has no bundler, so the browser gets whatever module graph the
client entry reaches and nothing can be eliminated. The entry is a named
export list rather than a wildcard re-export, and it is bundled once at
publish time. Unbundled that costs an app 255 requests and about 364 KB
gzipped; bundled it is 2 requests and 54 KB. The size budget is here
rather than in a later pull request because one wildcard re-export
silently undoes all of it.

Navigation tracing is the SDK's own, because `remix/ui` intercepts links
through the Navigation API and never touches History, so the upstream
handler would emit nothing. Page loads are ordinary document loads and
stay upstream.

Client error capture is a separate pull request.

Part of #24665

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>