Add a first cut of context menus, opened from the "more" (ellipsis)
button on Discover album cards and on album track rows.
- ContextMenu / ContextMenuItem primitives (PopupWindow-hosted panel)
- AlbumCard: the overlay action buttons are now interactive (they gate
their pointer handling so non-hovered cards still open on click); the
more button opens a menu — Open album, Play, Add to queue, Add to
favorites
- TrackRow: a hover-revealed more button opens a menu — Play, Add to
queue, Add to favorites; AlbumTrackItem and TrackData carry the
track id
- Menu actions bubble up as a single media-action(kind, id, action)
callback through the shell; main.rs logs it for now — playback and
favorites wiring lands with the playback session
- user and list-plus icons
cc
vicrodh
7eb9627eab