MusicStatusCard and Masonry Layout

MusicStatusCard Replaced the retired StatusCard with a MusicStatusCard displaying currently playing music with cover art from MusicBrainz. Extended the AT Protocol fetch layer with music status and artwork resolution utilities. Masonry layout Replaced the two-column grid with a masonry-style layout on the homepage. Added skeleton loaders for all card components, standardised card spacing, and optimised the mobile header with dropdown navigation.