fix(upload): set duplex for stream retry bodies

[sjinks]

Summary

• adds duplex: 'half' automatically in fetchWithRetry when an attempt uses a Node stream request body
• preserves caller-provided duplex values and keeps the one-shot stream retry guard from PR Fix file upload retry reusing an already-consumed stream body #2897
• adds a regression test that uses real undici.fetch with the repo's MockAgent test helper, so stream-body validation is exercised instead of mocked

Why

Follow-up from the v4.0.6 upload fix: a customer upgraded from the original Response body object should not be disturbed or locked failure and then hit:

RequestInit: duplex option is required when sending a body

PR #2897 correctly recreates stream bodies per retry, but the existing tests mock undici.fetch; they verify body recreation without exercising undici's real requirement that stream request bodies include duplex: 'half'.

Testing

• npm run jest -- __tests__/lib/fetch-with-retry-undici.js __tests__/lib/client-file-uploader.js --runInBand (ran all non-e2e suites: 56 passed / 593 tests)
• npm run check-types
• npm run cmd:lint -- src/lib/client-file-uploader.ts __tests__/lib/fetch-with-retry-undici.js
• npm run build

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[Copilot]

Pull request overview

This PR updates the upload retry helper to automatically set duplex: 'half' when a retry attempt uses a Node stream request body, addressing undici’s requirement for stream request bodies and adding a regression test intended to exercise real undici behavior.

Changes:

• Add stream-body detection and auto-inject duplex: 'half' in fetchWithRetry() when appropriate, while preserving caller-provided duplex.
• Refactor stream-body detection into a helper for reuse within fetchWithRetry().
• Add a Jest regression test that uses a local HTTP server to validate real undici stream-body behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/lib/client-file-uploader.ts	Adds duplex: 'half' automatically for stream request bodies during retry attempts.
__tests__/lib/fetch-with-retry-undici.js	Introduces a regression test intended to validate undici’s duplex requirement with real stream bodies.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud