First user-facing slice of the Discover-to-Sync unification. Adds a
ListenBrainz tab on the Sync page alongside Tidal / Qobuz /
Spotify Public / Beatport / etc. so users can mirror + auto-sync
ListenBrainz playlists from the same surface as every other source,
without detouring through the Discover page.
The Discover-page LB flow already owns all the heavy lifting
(state machine, discovery polling, sync → mirror creation). This
commit adds the Sync-page entry point only — list cached LB
playlists, render cards, pre-fetch tracks on click, hand off to
``openDownloadModalForListenBrainzPlaylist``. Zero backend changes.
- ``webui/index.html``: new ``<button data-tab="listenbrainz">`` +
tab content container with "For You / My Playlists /
Collaborative" sub-tabs and a refresh button.
- ``webui/static/sync-listenbrainz.js`` (new): ``loadListenBrainz
SyncPlaylists`` fetches all three LB cache categories in parallel,
``renderListenBrainzSyncPlaylists`` renders cards in the standard
``.youtube-playlist-card`` shell with the existing phase-state
helpers (so card colors / button text stay consistent with Tidal
/ Qobuz / etc.). Click handler populates the
``listenbrainzTracksCache`` from
``/api/discover/listenbrainz/playlist/<mbid>`` if not already
primed, then defers to the shared modal opener.
- ``webui/static/sync-services.js``: one new branch in
``initializeSyncPage`` to lazy-load the tab on first activation.
- ``webui/static/style.css``: ``.listenbrainz-icon`` SVG (orange
play-button in circle for inactive, white for active),
``.listenbrainz-sub-tab-btn`` styling for the sub-tabs,
``.refresh-button.listenbrainz`` accent.
- ``webui/static/helper.js``: WHATS_NEW entry under 2.6.3.
Auth-not-connected case is surfaced as a friendly placeholder
pointing the user at Settings → Connections instead of an empty
list.
a7053a6061
