* MeApi gains getListenBrainz + setListenBrainz (single PUT shape
with optional token / enabled fields, server treats untouched).
* MeRepository facade methods setListenBrainzToken / setListenBrainzEnabled.
* ListenBrainzStatus domain + ListenBrainzStatusWire (server never
echoes the token back; tokenSet is the visible signal).
* ListenBrainzViewModel — load on init, separate flows for save-token
and toggle-enabled, inline status message.
* ListenBrainzCard — descriptive copy, masked token field with
"Replace token" / "Token saved" placeholder, Save button, Switch
for "Send my plays" (disabled until a token is stored), "Last
scrobble: …" timestamp once present.
Slotted between PasswordCard and AppearanceCard.
About-panel update check is the second half of #20; lands in slice 2.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>