Improve tree shaking through Next.js module wrappers (#98638)
## What?
Extends the export-usage passthrough introduced by #98621 to the
transparent wrappers used for dynamic entries, server components, and
shared server utilities.
The existing reference-tree-shaking production fixture now covers each
wrapper and verifies that unused sibling exports do not remain in
Turbopack's server chunks.
## Why?
These wrappers forward another module's export surface, but previously
marked every target export as used. That kept otherwise unreachable
modules in production output and limited inner-graph tree shaking.
## How?
The dynamic-entry and server-component wrappers now pass their own
resolved export usage to their targets. The custom server-utility
reference reports the same passthrough binding usage while preserving
its shared chunking and merge behavior.
A public Turbopack constructor creates passthrough export-usage values
for references outside `turbopack-core`, consistent with the existing
constructors for other usage modes.
## Verification
- `cargo check -p next-core`
- `pnpm build-all`
- `pnpm test-start-turbo
test/production/app-dir/reference-tree-shaking/reference-tree-shaking.test.ts`
- `pnpm test-start-webpack
test/production/app-dir/reference-tree-shaking/reference-tree-shaking.test.ts`
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<!-- fleet df1472be-5cd1-4bd6-9fab-4efc1defa4f9 -->
Co-authored-by: vercel-fleet-prod[bot] <318278635+vercel-fleet-prod[bot]@users.noreply.github.com>
Co-authored-by: Tobias Koppers <1365881+sokra@users.noreply.github.com>
