fix(upload): publish stems sequentially after parent track

[dylanjeffers]

Problem

When uploading a contest track + stems simultaneously on audius.co, the UI gets permanently stuck on "Uploading Your Track" with red ⚠ error icons on every stem and the track itself — even though the upload succeeded (the contest page works after navigating away).

Reproducible on: Burko contest, Andrew Lux contest, Audius Summer Cypher Vol 2.

Root cause

In usePublishTracks.ts, publishParentTrack() and publishStems() were running concurrently via Promise.all:

// Before (race condition)
const [trackResult, stemsResults] = await Promise.all([
  publishParentTrack(),
  publishStems(context, { ..., parentTrackId: trackId })
])

publishStems received the trackId (generated by sdk.tracks.generateTrackId()) and passed it to each stem publish call — but because both ran in parallel, the stems were being published before the parent track was confirmed on-chain. Every publishStem API call failed as a result, dispatching ProgressStatus.ERROR for each stem row.

Fix

Await the parent track first, then publish stems:

// After (sequential, correct)
const trackResult = await publishParentTrack()
const stemsResults = await publishStems(context, { ..., parentTrackId: trackId })

This ensures the parent track is on-chain before any stem references it, eliminating the race condition.

[changeset-bot]

⚠️ No Changeset found

Latest commit: cb67462

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR