- Both steppers now show green checkmark on final step when completed
instead of leaving it highlighted as 'current' (blue)
- Stems error is cleared at the start of every generate_stems attempt,
not just on success — no stale error messages after retry
- Radio buttons in stems section use same compact spacing as checkboxes
- Webhook no longer overwrites cost estimate with 0 when conversion_cost
is missing from the payload
- Per-version costs (A/B) are tracked separately and summed into total
- Stems cost is only overwritten when a non-zero cost is reported
- Template shows combined total (songs + stems) with breakdown
- Added musicgpt_cost_a and musicgpt_cost_b columns to schema
- New /admin/request/<id>/download-stems endpoint
- Parses stems_url (label: url; label: url format), fetches each stem file,
bundles them into a zip served as an attachment download
- If MusicGPT returns a single .zip bundle URL, redirects directly
- Template button now points to the zip endpoint instead of raw CDN URLs
- Radio buttons to select Version A or B MP3 as stems source
- New /api/audio-source endpoint serves single MP3 for Extraction API
- Backend reads radio selection, constructs public URL automatically
- Download Stems button appears when stems are ready
- Generate button disabled when no MP3s are available
