- diagnostics_redact: keep '.psarc' in the song-filename scrub regex.
The purge swapped it for '.archive' (not a real extension), which
would leak real .psarc filenames still on users' disks into
diagnostic bundles. This is a redaction allow-list, not brand text.
- sloppak: the legacy lyrics-source alias was a no-op
({"notechart": "notechart"}), so old manifests with
lyrics_source=="sng" fell back to "xml" instead of migrating.
Map {"sng": "notechart"} so the rename stays back-compatible.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>