Preferences volume migration is a no-op on target data and clobbers muted=0

[ctoth]

Summary

The preferences "move volume from general to sound" migration is a no-op on exactly the data it targets, and separately clobbers a deliberately-muted volume: 0.

Details

src/stores/preferencesStore.ts:149-154:

if (parsed.general?.volume !== undefined && parsed.sound) {
  if (!parsed.sound.volume) {
    parsed.sound.volume = parsed.general.volume;
  }
  delete parsed.general.volume;
}

Two problems:

1. The data this migration exists to fix was written before sound existed, so it has no parsed.sound key. The && parsed.sound guard makes the whole block a no-op on precisely that data. The saved volume is lost (falls back to the default 1.0 at line 102), and the stale general.volume survives via the {...initial.general, ...stored.general} merge (line 121) and is re-persisted every save.

2. if (!parsed.sound.volume) treats a deliberate 0 (muted) as "absent" and overwrites it.

There is no schema-version field in the persisted shape, so migrated and unmigrated data are indistinguishable.

Fix direction

Migrate when general.volume is present regardless of whether sound exists (create it), and use sound.volume === undefined rather than falsiness so 0 is preserved. Consider adding a version field to the persisted blob.

Verification

Read src/stores/preferencesStore.ts end to end.