fix: complete empty TUS multipart uploads when Upload-Length is 0

[hsusul]

Summary

• Fixes Resumable (tus) upload creation with Upload-Length: 0 returns 404 with no explanation #1300: resumable upload creation with Upload-Length: 0 returned a bare 404 because TUS treats size-0 as immediately final (no write()), while @tus/s3-store create() only starts a multipart upload. Our onUploadFinish then HeadObjects a key that does not exist yet.
• Override S3Store.create to call upstream finishMultipartUpload(metadata, []) (which already uploads a zero-byte part when parts is empty), then complete metadata and clear cache, so the object exists before finish runs.
• Unit tests cover size 0 finalization and that non-zero / deferred sizes are unchanged.

Test plan

• npm run test:unit -- src/storage/protocols/tus/s3-store.test.ts
• Manual: POST /storage/v1/upload/resumable with Upload-Length: 0 and valid Upload-Metadata → 201, object exists as empty
• Manual: same with Upload-Length: 1 + PATCH still succeeds

[ferhatelmas]

Thanks, we need to fix it in upstream, not here. Could you direct your patch there? I can give look for review

[hsusul]

Thanks — agreed this belongs upstream.

Opened the fix in tus-node-server: tus/tus-node-server#876

Closing this PR in favor of that.